BALTIMORE GAS & ELECTRIC CO
SC 13D, 1998-10-08
ELECTRIC & OTHER SERVICES COMBINED
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                                  UNITED STATES
                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C.  20549

                                 SCHEDULE 13D

                   Under the Securities Exchange Act of 1934


                       Corporate Office Properties Trust
- - --------------------------------------------------------------------------------
                                (Name of Issuer)


                      Common Shares of Beneficial Interest
                          (par value $0.01 per share)

          Series A Convertible Preferred Shares of Beneficial Interest
                           (par value $0.01 per share)
- - --------------------------------------------------------------------------------
                         (Title of Class of Securities)


                                   22002T108
- - --------------------------------------------------------------------------------
                                 (CUSIP Number)


                                Dan R. Skowronski
                         General Counsel and Secretary
                         Constellation Properties, Inc.
                         250 W. Pratt Street, 23rd Floor
                         Baltimore, Maryland 21201-2423
                                 (410) 783-2814
- - --------------------------------------------------------------------------------
                 (Name, Address and Telephone Number of Person
               Authorized to Receive Notices and Communications)


                               September 28, 1998
- - --------------------------------------------------------------------------------
                      (Date of Event which Requires Filing
                               of this Statement)

If the filing person has previously  filed a statement of Schedule 13G to report
the  acquisition  which is the subject of the  Schedule  13D, and is filing this
schedule because of Rule 13d-1(b)(3) or (4), check the following box [ ].

                                  page 1 of 15


<PAGE>

CUSIP No.   22002T108

- - --------------------------------------------------------------------------------
   1   NAME OF REPORTING PERSON:  Baltimore Gas and Electric Company
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON:  52-0280210

- - --------------------------------------------------------------------------------
   2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                             (a)  [  ]
                                                             (b)  [  ]
- - --------------------------------------------------------------------------------
   3   SEC USE ONLY

- - --------------------------------------------------------------------------------
   4   SOURCE OF FUNDS*

       OO
- - --------------------------------------------------------------------------------
   5   CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
       ITEMS 2(d) OR 2(e)                                         [  ]

- - --------------------------------------------------------------------------------
   6   CITIZENSHIP OR PLACE OF ORGANIZATION

       Maryland
- - --------------------------------------------------------------------------------
   NUMBER OF      7    SOLE VOTING POWER
     SHARES            6,182,634*
  BENEFICIALLY    --------------------------------------------------------------
    OWNED BY      8    SHARED VOTING POWER
      EACH             0*
   REPORTING      --------------------------------------------------------------
     PERSON       9    SOLE DISPOSITIVE POWER
      WITH             6,182,634*
                  --------------------------------------------------------------
                  10   SHARED DISPOSITIVE POWER
                       0*
- - --------------------------------------------------------------------------------
  11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

       6,182,634*

- - --------------------------------------------------------------------------------
  12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*

                                                                      [  ]
- - --------------------------------------------------------------------------------
  13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

      38.8%
- - --------------------------------------------------------------------------------
  14   TYPE OF REPORTING PERSON*

       CO
- - --------------------------------------------------------------------------------
              * Common Shares of Beneficial Interest of the Issuer
        Represents Common Shares held by Constellation Properties, Inc.

                                  Page 2 of 15

<PAGE>

CUSIP No.   22002T108

- - --------------------------------------------------------------------------------
   1   NAME OF REPORTING PERSON:  Baltimore Gas and Electric Company
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON:  52-0280210

- - --------------------------------------------------------------------------------
   2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                             (a)  [  ]
                                                             (b)  [  ]
- - --------------------------------------------------------------------------------
   3   SEC USE ONLY

- - --------------------------------------------------------------------------------
   4   SOURCE OF FUNDS*

       OO
- - --------------------------------------------------------------------------------
   5   CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
       ITEMS 2(d) OR 2(e)                                         [  ]

- - --------------------------------------------------------------------------------
   6   CITIZENSHIP OR PLACE OF ORGANIZATION

       Maryland
- - --------------------------------------------------------------------------------
   NUMBER OF      7    SOLE VOTING POWER
     SHARES            865,566*
  BENEFICIALLY    --------------------------------------------------------------
    OWNED BY      8    SHARED VOTING POWER
      EACH             0*
   REPORTING      --------------------------------------------------------------
     PERSON       9    SOLE DISPOSITIVE POWER
      WITH             865,566*
                  --------------------------------------------------------------
                  10   SHARED DISPOSITIVE POWER
                       0*
- - --------------------------------------------------------------------------------
  11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

       865,566*
- - --------------------------------------------------------------------------------
  12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*

                                                                      [  ]
- - --------------------------------------------------------------------------------
  13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

       100%
- - --------------------------------------------------------------------------------
  14   TYPE OF REPORTING PERSON*

       CO
- - --------------------------------------------------------------------------------
  * Series A Convertible Preferred Shares of Beneficial Interest of the Issuer
     Represents Series A Convertible Preferred Shares held by Constellation
                                Properties, Inc.

                                  Page 3 of 15

<PAGE>

CUSIP No.   22002T108

- - --------------------------------------------------------------------------------
   1   NAME OF REPORTING PERSON:  Constellation Enterprises, Inc.
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON:  52-2080643

- - --------------------------------------------------------------------------------
   2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                             (a)  [  ]
                                                             (b)  [  ]
- - --------------------------------------------------------------------------------
   3   SEC USE ONLY

- - --------------------------------------------------------------------------------
   4   SOURCE OF FUNDS*

       OO
- - --------------------------------------------------------------------------------
   5   CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
       ITEMS 2(d) OR 2(e)                                         [  ]

- - --------------------------------------------------------------------------------
   6   CITIZENSHIP OR PLACE OF ORGANIZATION

       Maryland
- - --------------------------------------------------------------------------------
   NUMBER OF      7    SOLE VOTING POWER
     SHARES            6,182,634*
  BENEFICIALLY    --------------------------------------------------------------
    OWNED BY      8    SHARED VOTING POWER
      EACH             0*
   REPORTING      --------------------------------------------------------------
     PERSON       9    SOLE DISPOSITIVE POWER
      WITH             6,182,634*
                  --------------------------------------------------------------
                  10   SHARED DISPOSITIVE POWER
                       0*
- - --------------------------------------------------------------------------------
  11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

       6,182,634*
- - --------------------------------------------------------------------------------
  12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*

                                                                      [  ]
- - --------------------------------------------------------------------------------
  13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

       38.8%
- - --------------------------------------------------------------------------------
  14   TYPE OF REPORTING PERSON*

       CO
- - --------------------------------------------------------------------------------
              * Common Shares of Beneficial Interest of the Issuer
        Represents Common Shares held by Constellation Properties, Inc.


                                  Page 4 of 15



<PAGE>


CUSIP No.   22002T108

- - --------------------------------------------------------------------------------
   1   NAME OF REPORTING PERSON:  Constellation Enterprises, Inc.
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON:  52-2080643

- - --------------------------------------------------------------------------------
   2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                             (a)  [  ]
                                                             (b)  [  ]
- - --------------------------------------------------------------------------------
   3   SEC USE ONLY

- - --------------------------------------------------------------------------------
   4   SOURCE OF FUNDS*

       OO
- - --------------------------------------------------------------------------------
   5   CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
       ITEMS 2(d) OR 2(e)                                         [  ]

- - --------------------------------------------------------------------------------
   6   CITIZENSHIP OR PLACE OF ORGANIZATION

       Maryland
- - --------------------------------------------------------------------------------
   NUMBER OF      7    SOLE VOTING POWER
     SHARES            865,566*
  BENEFICIALLY    --------------------------------------------------------------
    OWNED BY      8    SHARED VOTING POWER
      EACH             0*
   REPORTING      --------------------------------------------------------------
     PERSON       9    SOLE DISPOSITIVE POWER
      WITH             865,566*
                  --------------------------------------------------------------
                  10   SHARED DISPOSITIVE POWER
                       0*
- - --------------------------------------------------------------------------------
  11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

       865,566*
- - --------------------------------------------------------------------------------
  12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*

                                                                      [  ]
- - --------------------------------------------------------------------------------
  13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

       100%
- - --------------------------------------------------------------------------------
  14   TYPE OF REPORTING PERSON*

       CO
- - --------------------------------------------------------------------------------
  * Series A Convertible Preferred Shares of Beneficial Interest of the Issuer
     Represents Series A Convertible Preferred Shares held by Constellation
                                Properties, Inc.

                                  Page 5 of 15


<PAGE>


CUSIP No.   22002T108

- - --------------------------------------------------------------------------------
   1   NAME OF REPORTING PERSON:  Constellation Properties, Inc.
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON:  52-1237835

- - --------------------------------------------------------------------------------
   2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                             (a)  [  ]
                                                             (b)  [  ]
- - --------------------------------------------------------------------------------
   3   SEC USE ONLY

- - --------------------------------------------------------------------------------
   4   SOURCE OF FUNDS*

       OO
- - --------------------------------------------------------------------------------
   5   CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
       ITEMS 2(d) OR 2(e)                                         [  ]

- - --------------------------------------------------------------------------------
   6   CITIZENSHIP OR PLACE OF ORGANIZATION

       Maryland
- - --------------------------------------------------------------------------------
   NUMBER OF      7    SOLE VOTING POWER
     SHARES            6,182,634*
  BENEFICIALLY    --------------------------------------------------------------
    OWNED BY      8    SHARED VOTING POWER
      EACH             0*
   REPORTING      --------------------------------------------------------------
     PERSON       9    SOLE DISPOSITIVE POWER
      WITH             6,182,634*
                  --------------------------------------------------------------
                  10   SHARED DISPOSITIVE POWER
                       0*
- - --------------------------------------------------------------------------------
  11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

       6,182,634*
- - --------------------------------------------------------------------------------
  12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*

                                                                      [  ]
- - --------------------------------------------------------------------------------
  13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

       38.8%
- - --------------------------------------------------------------------------------
  14   TYPE OF REPORTING PERSON*

       CO
- - --------------------------------------------------------------------------------
              * Common Shares of Beneficial Interest of the Issuer



                                  Page 6 of 15



<PAGE>


CUSIP No.   22002T108

- - --------------------------------------------------------------------------------
   1   NAME OF REPORTING PERSON:  Constellation Properties, Inc.
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON:  52-1237835

- - --------------------------------------------------------------------------------
   2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                             (a)  [  ]
                                                             (b)  [  ]
- - --------------------------------------------------------------------------------
   3   SEC USE ONLY

- - --------------------------------------------------------------------------------
   4   SOURCE OF FUNDS*

       OO
- - --------------------------------------------------------------------------------
   5   CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
       ITEMS 2(d) OR 2(e)                                         [  ]

- - --------------------------------------------------------------------------------
   6   CITIZENSHIP OR PLACE OF ORGANIZATION

       Maryland
- - --------------------------------------------------------------------------------
   NUMBER OF      7    SOLE VOTING POWER
     SHARES            865,566*
  BENEFICIALLY    --------------------------------------------------------------
    OWNED BY      8    SHARED VOTING POWER
      EACH             0*
   REPORTING      --------------------------------------------------------------
     PERSON       9    SOLE DISPOSITIVE POWER
      WITH             865,566*
                  --------------------------------------------------------------
                  10   SHARED DISPOSITIVE POWER
                       0*
- - --------------------------------------------------------------------------------
  11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

       865,566*
- - --------------------------------------------------------------------------------
  12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*

                                                                      [  ]
- - --------------------------------------------------------------------------------
  13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

       100%
- - --------------------------------------------------------------------------------
  14   TYPE OF REPORTING PERSON*

       CO
- - --------------------------------------------------------------------------------
  * Series A Convertible Preferred Shares of Beneficial Interest of the Issuer


                                  Page 7 of 15

<PAGE>


         Item 1.  Security and Issuer.

         This  statement on Schedule 13D relates to Common  Shares of Beneficial
Interest,  par value $0.01 per share (the "Common Shares"),  of Corporate Office
Properties  Trust, a Maryland real estate  investment trust (the "Issuer"),  and
Series A Convertible  Preferred Shares of Beneficial  Interest,  par value $0.01
per share (the "Preferred Shares"),  of the Issuer. The Issuer has its principal
executive offices at One Logan Square,  Suite 1105,  Philadelphia,  Pennsylvania
19103.

         Item 2.  Identity and Background.

         This  statement  on Schedule  13D is being filed on behalf of Baltimore
Gas and Electric Company ("BGE"),  Constellation  Enterprises,  Inc. ("CEI") and
Constellation Properties, Inc. ("CPI") (collectively,  the "Reporting Persons").
BGE is a Maryland  corporation  and has its  principal  business  and  executive
offices at 39 West Lexington Street, Baltimore, Maryland 21201. BGE is primarily
engaged in the gas and  electric  utility  business.  The Common  Shares and the
Preferred  Shares are owned of record by CPI, which is a wholly owned subsidiary
of  Constellation  Real Estate  Group,  Inc.  ("CREG"),  which is a wholly owned
subsidiary of  Constellation  Holdings,  Inc.  ("CHI"),  which is a wholly owned
subsidiary of CEI, which is a wholly owned subsidiary of BGE. Each of CPI, CREG,
CHI and CEI is a  Maryland  corporation  and has  its  principal  executive  and
business offices at 250 West Pratt Street, Baltimore, Maryland 21201-2423.

         None of the  Reporting  Persons have,  during the last five years,  (i)
been convicted in a criminal  proceeding  (excluding minor traffic violations or
similar  misdemeanors)  or (ii) been a party to a civil proceeding of a judicial
or administrative body of competent  jurisdiction a result of which it was or is
subject to a judgment, decree or final order enjoining future violations of,. or
prohibiting or mandating activities subject to, federal or state securities laws
or finding any violations with respect to such laws.

         Item 3.  Source and Amount of Funds or Other Consideration.

         CPI,  acquired  the  securities  of the  Issuer  pursuant  to  (i)  the
Contribution Agreement (the "Contribution  Agreement") dated as of May 14, 1998,
by and among the  entities  listed  as  sellers  therein  and  Corporate  Office
Properties,  L.P. and the Issuer,  as amended on July 16, 1998 and September 28,
1998;  and (ii) the Service  Company Asset  Contribution  Agreement  (the "Asset
Contribution  Agreement")  dated May 14, 1998, by and among  Constellation  Real
Estate, Inc., KMS Oldco, Inc., CREG,  Corporate Office Properties,  L.P. and the
Issuer. BGE, through its subsidiaries,  contributed real property,  interests in
entities that own real  property and a mortgage,  and other assets to the Issuer
in exchange for cash,  assumption  of $59.6 million of  indebtedness,  6,182,634
Common Shares and 865,566  Preferred Shares of the Issuer.  The Preferred Shares
do not  entitle  the holder  thereof  to any vote,  except  (i) as  required  by
applicable law, (ii) in connection with an amendment to the Issuer's Declaration
of Trust that would  amend,  alter or repeal any of the rights,  preferences  or
powers of the Preferred Shares or (iii) the right to designate up to two members
of  the  Board  of  Trustees  as  described  below.  The  Preferred  Shares  are
convertible,   beginning  two  years  after  the  closing  of  the  transactions
contemplated by the Contribution  Agreement and the Asset Contribution Agreement
(the "Transaction"), into Common Shares on the basis of 1.8748 Common Shares for


                                  Page 8 of 15

<PAGE>



each Preferred Share,  subject to adjustment upon certain events,  in accordance
with the  terms and  provisions  of the  Articles  Supplementary  of the  Issuer
relating to such Preferred Shares filed with the State Department of Assessments
and Taxation of Maryland.

         Item 4.  Purpose of Transaction.

         CPI,  acquired the  securities  of the Issuer as an  investment  and in
consideration  of the assets  transferred  to the Issuer as  described in Item 3
above.  After the closing of the  Transaction,  the Issuer expanded its Board of
Trustees from seven to nine,  and the Issuer  elected  thereto Edward A. Crooke,
Chairman of Constellation Enterprises, Inc. and Vice Chairman of BGE, and Steven
D.  Kesler,  President of  Constellation  Investments,  Inc.,  each of whom were
designated  by CPI in  accordance  with its  rights as the  holder of  Preferred
Shares.  Mr. Crooke is a Class III Trustee  whose term expires in 2001,  and Mr.
Kesler is a Class II Trustee  whose term  expires in 2000.  If any member of the
Board of Trustees  designated by CPI withdraws for any reason, CPI will have the
right to designate such withdrawing Trustee's replacement.  Thereafter, CPI will
be entitled to designate  two Trustees as long as it owns any  Preferred  Shares
and at least 30% of the Issuer's outstanding Common Shares, and will be entitled
to designate one Trustee as long as it owns any  Preferred  Shares and less than
30%  but  more  than  15%  of  the  outstanding  Common  Shares.  The  foregoing
calculations  include as  outstanding  the Common Shares owned by CPI as well as
the Common  Shares  issuable upon  conversion of Preferred  Shares owned by CPI.
Moreover,  if the Issuer  fails at any time or from time to time to pay when due
two consecutive  quarterly  dividend payments on the Preferred Shares,  then the
holders of the Preferred Shares will be entitled to elect two additional members
to the Board of  Trustees  of the Issuer to serve  until all  accrued and unpaid
dividends on the Preferred Shares have been paid in full.

         The Issuer has  granted  registration  rights with regard to the Common
Shares  to CPI in  exchange  for the  consideration  described  in Item 3 above,
pursuant to the  Registration  Rights Agreement dated September 28, 1998, by the
Issuer and certain persons named therein. Within six months after the closing of
the Transaction,  the Issuer is obligated to file a shelf registration statement
with  regard to the  Common  Shares  issued in the  Transaction,  as well as the
Common Shares issuable upon conversion of the Preferred Shares (the "Registrable
Securities").  The Issuer is also  required,  at the demand of holders of 10% or
more of the  Registrable  Securities,  to  register  such  holders'  Registrable
Securities,  subject  to  the  right  to  defer  the  filing  of  the  necessary
registration  statement for a period not to exceed 90 days under certain limited
circumstances.   In  addition,  the  Issuer  has  granted  the  holders  of  the
Registrable Securities "piggy-back" rights.

         After  the  closing  of the  Transaction,  Jay H.  Shidler  remains  as
Chairman  and Clay W.  Hamlin,  III  remains as Chief  Executive  Officer of the
Issuer.  Randall M. Griffin,  formerly  President of CREG,  became President and
Chief  Operating  Officer of the Issuer.  In addition,  Roger A.  Waesche,  Jr.,
formerly Senior Vice President of Finance of  Constellation  Real Estate,  Inc.,
became Senior Vice President-Finance of the Issuer and John H. Gurley,  formerly
Vice President and General  Counsel of  Constellation  Real Estate,  Inc. became
Vice President and General Counsel of the Issuer.

                                  Page 9 of 15

<PAGE>



         After the closing of the  Transaction,  the Issuer  expects to close on
additional  properties  held by CPI or its affiliates  that are currently  under
construction or  development.  The closing of two of the properties is scheduled
to  occur on the  earlier  of  December  31,  1998 or the date on which  certain
occupancy  levels are  achieved on one of the  properties  and on the earlier of
March 31, 1999 or the date on which certain occupancy levels are achieved on the
other  property.  The  total  consideration  to be  paid by the  Issuer  for the
properties  will include,  inter alia,  approximately  846,143 Common Shares and
118,460 Preferred Shares.

         Except as set forth above, the Reporting  Persons do not have as of the
date hereof any plans or  proposals  that relate to or would  result in: (i) the
acquisition  of  additional  securities  of the  Issuer  or the  disposition  of
securities of the Issuer; (ii) an extraordinary corporate transaction, such as a
merger,  reorganization  or  liquidation  involving  the  Issuer  or  any of its
subsidiaries;  (iii) a sale or  transfer  of a material  amount of assets of the
Issuer  or any of its  subsidiaries;  (iv) any  change in the  present  Board of
Trustees or management of the Issuer, including any plans or proposals to change
the number or term of trustees or to fill any  vacancies  of the Board;  (v) any
material change in the present  capitalization or dividend policy of the Issuer;
(vi) any other material change in the Issuer's business or corporate  structure;
(vii) any changes in the Issuer's  declaration of trust,  by-laws or instruments
corresponding  thereto or other  actions  which may impede  the  acquisition  of
control of the Issuer by any person; (viii) causing a class of securities of the
Issuer to be  delisted  from a national  securities  exchange  or to cease to be
authorized  to be quoted in an  inter-dealer  quotation  system of a  registered
national  securities  association;  (ix)  causing a class of  securities  of the
Issuer to become eligible for  termination of  registration  pursuant to Section
12(g)(4) of the Securities  Exchange Act of 1934, as amended;  or (x) any action
similar  to any of  those  enumerated  above.  Notwithstanding  anything  to the
contrary  contained  herein,  the Reporting  Persons reserve the right to change
their  present  intentions  with  respect  to  the  matters  described  in  this
paragraph.

         Item 5.  Interest in Securities of Issuer.

         Based upon the Issuer's Quarterly Report on Form 10-Q for the quarterly
period ended June 30, 1998 filed with the  Securities  and  Exchange  Commission
under the Securities Exchange Act of 1934, as amended, as of September 28, 1998,
15,953,717 Common Shares are issued and outstanding and 865,566 Preferred Shares
are issued and  outstanding.  The Reporting  Persons have sole power to vote and
dispose of 6,182,634 Common Shares,  which  constitutes 38.8% of the outstanding
Common Shares,  and 865,566  Preferred  Shares,  which  constitutes  100% of the
outstanding Preferred Shares.

         Item 6.  Contracts,  Arrangements,  Understandings  or  Relationships 
with Respect to  Securities  of the Issuer.

         There are  presently  no  contracts,  arrangements,  understandings  or
relationships  (legal or otherwise)  among the persons filing this Schedule 13D,
or between such persons and any other person,  with respect to any securities of
the Issuer, including, but not limited to, transfer or voting of any securities,
finder's  fees,  joint  ventures,  loan or option  arrangements,  puts or calls,
guarantees or profits, division of profits or loss, or the giving or withholding
of proxies.

                                  Page 10 of 15

<PAGE>



         The Issuer has  granted  registration  rights with regard to the Common
Shares  to CPI in  exchange  for the  consideration  described  in Item 3 above,
pursuant to the  Registration  Rights Agreement dated September 28, 1998, by the
Issuer and certain persons named therein. Within six months after the closing of
the Transaction,  the Issuer is obligated to file a shelf registration statement
with  regard to the  Common  Shares  issued in the  Transaction,  as well as the
Common Shares issuable upon conversion of the Preferred Shares (the "Registrable
Securities").  The Issuer is also  required,  at the demand of holders of 10% or
more of the  Registrable  Securities,  to  register  such  holders'  Registrable
Securities,  subject  to  the  right  to  defer  the  filing  of  the  necessary
registration  statement for a period not to exceed 90 days under certain limited
circumstances.   In  addition,  the  Issuer  has  granted  the  holders  of  the
Registrable Securities "piggy-back" rights.

                                     page 11 of 15

<PAGE>



         Item 7.  Material to be filed as Exhibits



             Exhibit No.                                Document
                 1.                    Contribution  Agreement  dated as of May
                                       14, 1998,  by  and  among   the  entities
                                       listed  as  sellers therein and Corporate
                                       Office  Properties,  L.P.  and  Corporate
                                       Office Properties Trust.

                 2.                    First Amendment to Contribution Agreement
                                       dated as of July 16, 1998, by and between
                                       Corporate  Office  Properties  Trust  and
                                       Corporate Office Properties, L.P. and the
                                       sellers named therein.

                 3.                    Second    Amendment    to    Contribution
                                       Agreement dated as of September 28, 1998,
                                       by   and   between    Corporate    Office
                                       Properties  Trust  and  Corporate  Office
                                       Properties,  L.P.  and the sellers  named
                                       therein.

                 4.                    Service   Company   Asset    Contribution
                                       Agreement,  dated  May 14,  1998,  by and
                                       among  Constellation  Real Estate,  Inc.,
                                       KMS Oldco,  Inc., CREG,  Corporate Office
                                       Properties, L.P. and the Issuer.

                 5.                    Registration   Rights   Agreement   dated
                                       September  28,  1998,  by the  Issuer and
                                       certain persons named therein.

                 6.                    Articles   Supplementary   of   Corporate
                                       Office  Properties Trust  classifying the
                                       Series A Convertible  Preferred Shares of
                                       Beneficial Interest.

                                  page 12 of 15

<PAGE>


                                    SIGNATURE



         After reasonable  inquiry and to the best of my knowledge and belief, I
certify that the information  set forth in this statement is true,  complete and
correct.

Dated:  October 8, 1998

                               BALTIMORE GAS AND ELECTRIC COMPANY

                               By:    /s/ David A. Brune
                               Name:  David A. Brune
                               Title:  Vice President, Finance and Accounting,
                                       Chief Financial Officer and Secretary

                                  Page 13 of 15

<PAGE>



                                   SIGNATURE





         After reasonable  inquiry and to the best of my knowledge and belief, I
certify that the information  set forth in this statement is true,  complete and
correct.



Dated:  October 8, 1998


                               CONSTELLATION ENTERPRISES, INC.

                               By:   /s/ David A. Brune
                               Name:  David A. Brune
                               Title:  Vice President, Chief Financial Officer
                                       and Secretary

                                  page 14 of 15

<PAGE>

                                   SIGNATURE




        After reasonable  inquiry and to the best of my knowledge and belief, I
certify that the information  set forth in this statement is true,  complete and
correct.





Dated:  October 8, 1998


                                    CONSTELLATION PROPERTIES, INC.

                                    By:  /s/ Dan R. Skowronski
                                    Name:  Dan R. Skowronski
                                    Title:  General Counsel and Secretary



                                  Page 15 of 15







                             CONTRIBUTION AGREEMENT

                                     Between

                      CORPORATE OFFICE PROPERTIES TRUST AND
                       CORPORATE OFFICE PROPERTIES, L.P.,
                               COLLECTIVELY, BUYER

                                       and

                            THE SELLERS LISTED ON THE
                        SIGNATURE PAGE TO THIS AGREEMENT


                      (Constellation Real Estate Portfolio/
                              Completed Properties)

                         Dated as of May 14, 1998


         IN MAKING AN INVESTMENT DECISION INVESTORS MUST RELY ON THEIR OWN
         EXAMINATION OF THE ISSUER AND THE TERMS OF THE OFFERING, INCLUDING THE
         MERITS AND RISKS INVOLVED. THE SECURITIES REFERENCED HEREIN HAVE NOT
         BEEN RECOMMENDED BY ANY FEDERAL OR STATE SECURITIES COMMISSION OR
         REGULATORY AUTHORITY. FURTHERMORE, THE FOREGOING AUTHORITIES HAVE NOT
         CONFIRMED THE ACCURACY OR ADEQUACY OF THIS DOCUMENT. ANY REPRESENTATION
         TO THE CONTRARY IS A CRIMINAL OFFENSE.

         THESE SECURITIES ARE SUBJECT TO RESTRICTIONS ON TRANSFERABILITY AND
         RESALE AND MAY NOT BE TRANSFERRED OR RESOLD EXCEPT AS PERMITTED UNDER
         THE SECURITIES ACT OF 1933, AS AMENDED, AND THE APPLICABLE STATE
         SECURITIES LAWS, PURSUANT TO REGISTRATION OR EXEMPTION THEREFROM.
         INVESTORS SHOULD BE AWARE THAT THEY MAY BE REQUIRED TO BEAR THE
         FINANCIAL RISK OF THIS INVESTMENT FOR AN INDEFINITE PERIOD OF TIME.



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         THIS CONTRIBUTION AGREEMENT is made and entered into as of this 14th
day of May, 1998 (the "Contract Date"), by and between the entities
listed on the signature page to this Agreement as Sellers and also identified on
Exhibit "Sellers" attached hereto (collectively, the "Sellers" and each
individually, a "Seller"), Corporate Office Properties, L.P., a Delaware limited
partnership ("COPLP"). and Corporate Office Properties Trust, a Maryland real
estate investment trust ("REIT") (COPLP and the REIT, hereinafter collectively
the "Buyer").

                                   Background

         The Sellers, except for CPI (as defined below) only as to Tred Avon (as
defined below), own one hundred percent (100%) of the Interests (the
"Interests") of the entities and limited liability companies identified on
Exhibit "Entities" (the "Entities"). Each Entity (except Tred Avon) is the
record and beneficial owner of its respective Project or Projects (as defined
below) identified on Exhibit "Projects", and CPI is the record and beneficial
owner of fee simple title to the Project known as Brandon (defined below). Tred
Avon is the record and beneficial owner of the Tred Avon Loan Documents (defined
below). The Interest of each Seller (which is such Seller's full capital,
profits, voting and other interest in the subject Entity) in each Entity is set
forth on Exhibit "Sellers".

         The Projects include the Land and those certain buildings (the
"Buildings"), each containing that number of net rentable square feet, as
specified on Exhibit "Projects" attached hereto. The Buildings are leased by the
Entities (except Tred Avon) and CPI as to Brandon, to Tenants (as defined below)
for office and retail purposes. Each of the Buildings is commonly known by the
respective street address in the cities, counties and states described on
Exhibit "Projects" attached hereto. For purposes of this Agreement the term,
"Projects," shall be deemed to mean, on a collective basis with respect to each
Entity or Seller, as applicable: (i) all of the parcels of land identified on
Exhibit "Projects" attached hereto (collectively, the "Land"), together with all
rights, easements and interests appurtenant thereto, including, but not limited
to, any streets or other public ways adjacent to such Land and any water or
mineral rights owned by, or leased to, such Entity or CPI as to Brandon; (ii)
all improvements located on the Land, including, but not limited to, the
Buildings, and all other structures, systems, and utilities associated with, and
utilized by, such Entity, or CPI as to Brandon in the ownership and operation of
the Buildings (all such improvements being collectively referred to herein as
the "Improvements"), but excluding improvements, if any, owned by Tenants of
such applicable Buildings; (iii) all personal property owned by such Seller or
Entity, or CPI as to Brandon and either (A) located on or in the Land or
Improvements, or (B) used in connection with the operation and maintenance of
the Project (collectively, the "Personal Property"); (iv) all building
materials, supplies, hardware, carpeting and other inventory owned by such
Entity or Seller, or CPI as to Brandon and maintained in connection with such
Entity's or CPI's ownership and operation of the Land and/or Improvements
(collectively, the "Inventory"); (v) all trademarks, tradenames, development
rights and entitlements and other intangible property used or useful in
connection with the foregoing (collectively, the "Intangible Personal
Property"), except the right to use

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the name Constellation; and (vi) such Entity's interest, and CPI's interest as
to Brandon, in all leases and other agreements to occupy all or any portion of
the Land and/or Improvements in effect on the Contract Date or into which such
Entity or CPI enters prior to the Closing (as defined below), but pursuant to
the express terms of this Agreement (collectively, the "Leases").

         The Sellers and Buyer desire to enter this Agreement relating to the
sale by the Sellers to Buyer of Interests, and the sale by CPI to Buyer of
Brandon, in exchange for cash, debt assumption, and Shares (as defined below)
pursuant to the terms of this Agreement.

         NOW, THEREFORE, for and in consideration of the mutual covenants and
agreements contained in this Agreement, and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, and
intending to be legally bound, the parties agree as follows:

         1.        DEFINITIONS.

         All terms which are not otherwise defined in this Contribution
Agreement shall have the meaning set forth in this Section 1.

                  1.1. "Accredited Investor" shall have the meaning set forth in
Regulation D promulgated under the Securities Act of 1933, as amended.

                  1.2. "Additional Rent" shall have the meaning set forth
in Section 15.1.5.

                  1.3. "Affiliate(s)" shall have the meaning set forth in
Section 21.

                  1.4. "Assumed Indebtedness" shall mean (a) the outstanding
principal balance of the indebtedness as of the Closing Date of those two (2)
Entities identified on Exhibit "Assumed Indebtedness" with respect to those two
(2) Projects identified on Exhibit "Assumed Indebtedness" as such indebtedness
is described (including a statement of the outstanding principal balance as of
the date of this Agreement) on Exhibit "Assumed Indebtedness" and (b) the
outstanding principal balance as of the Closing Date of such portion of the
Satisfied Indebtedness that Buyer, in its sole discretion, elects to assume. The
Assumed Indebtedness identified in clause (a) of the preceding sentence is
evidenced and secured by the Assumed Loan Documents described on Exhibit
"Assumed Loan Documents". Buyer's right to assume the Assumed Indebtedness is
subject to the provisions of Section 3.2.7.

                  1.5. "Assumed Loan Documents" shall mean the documents
evidencing or securing the Assumed Indebtedness, as described on Exhibit
"Assumed Loan Documents".

                  1.6. "Base Rent" shall have the meaning set forth in
 Section 15.1.5.

                                       3

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                  1.7.  "Brandon" shall mean the Project located at 7609 
Energy Parkway, Anne Arundel County, Maryland and identified as Brandon on
Exhibit "Projects".

                  1.8.  "Buildings" shall have the meaning set forth in the
recitals to this Agreement.

                  1.9.  "Buyer" shall mean collectively the REIT (as defined
below) and Corporate Office Properties, L.P., a Delaware limited partnership the
sole general partner of which is the REIT.

                  1.10. "Buyer Indemnified Parties" shall have the meaning set
 forth in Section 13.3.

                  1.11. "Buyer's Closing Notice" shall have the meaning set
forth in Section 6.1.

                  1.12. "Buyer's Request" shall have the meaning set forth
in Section 6.3.

                  1.13. "Buyer's Conditions Precedent" shall mean all
conditions precedent to Buyer's obligations to close as set forth in this
Agreement.

                  1.14. "Buyer's Reasonable Costs" shall mean all out-of-pocket
costs and expenses incurred by Buyer in connection with this Agreement and the
Projects, including, but not limited to, legal fees, title company charges,
engineering fees, environmental consultant's fees, architects' and surveyors'
fees and other similar charges.

                  1.15. "CPI" shall mean Constellation Properties, Inc., a
Maryland corporation.

                  1.16. "CPI Affiliates" shall mean entities controlled by CPI.

                  1.17. "Cash Component" shall have the meaning set forth in
Section 3.

                  1.18. "Certification of Default" shall have the meaning
set forth in Section 6.3.

                  1.19. "Closing" shall mean (a) the occurrence of the events
described in Section 6.1 as to all Sellers, other than the NBP 135 Sellers and
Woodlands Sellers, and defined in Section 6.1 as the First Closing, (b) the
occurrence of the events described in Section 6.2.1 as to the NBP 135 Sellers
and defined in Section 6.2.1 as the NBP 135 Closing, and (c) the occurrence of
the events described in Section 6.2.2 as to Woodlands, and defined in Section
6.2.2 as the Woodlands Closing.

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                  1.20. "Closing Date" shall mean (a) the date set forth in
Section 6.1 as to all Sellers, other than the NBP 135 Sellers and the Woodlands
Sellers, and defined in Section 6.1 as the First Closing Date, (b) the date set
forth in Section 6.2.1 as to the NBP 135 Sellers and defined in Section 6.2.1 as
the NBP 135 Closing Date, and (c) the date set forth in Section 6.2.2 as to the
Woodlands Sellers and defined in Section 6.2.2 as the Woodlands Closing Date.

                  1.21. "Closing Statement" shall have the meaning set forth
in Section 16.1.11.

                  1.22. "Common Share Amount" shall have the meaning set
forth in Section 3.2.3 below.

                  1.23. "Common Shares" means common shares of the REIT.

                  1.24. "Consideration" shall have the meaning set forth in
Section 3.

                  1.25. "Constellation Lease" shall have the meaning set forth
in Section 5.6.

                  1.26. "Contract Date" shall mean the date set forth in the
first paragraph of this Agreement.

                  1.27. "Convertible Preferred Shares" shall mean convertible
cumulative preferred shares of the REIT to be classified and issued by the REIT
in accordance with the Amended and Restated Declaration of Trust of the REIT as
amended. Each Convertible Preferred Share has a liquidation preference of $25.00
and pays a cumulative dividend of 5.5% per year. The dividend shall have a
preference over dividends payable on the Common Shares. Each Convertible
Preferred Share is convertible into Common Shares at an initial conversion price
of $13.335 per Common Share (subject to anti-dilution adjustments) and otherwise
subject to the terms of the Amended and Restated Declaration of Trust of the
REIT, as may be further amended. Convertible Preferred Shares delivered to
Sellers at Closing under this Agreement shall not be converted before two (2)
years after the Closing Date and shall not be converted if such conversion would
result in the Sellers owning, in the aggregate, more than forty-five percent
(45%) in the aggregate of the outstanding Common Shares of the REIT.
Notwithstanding the foregoing, if there is a change in control of the REIT, the
two year prohibition against conversion shall be deemed to have terminated and
the Convertible Preferred Shares may thereafter be converted into Common Shares
(subject, however, to the 45% limitation and to the terms of the Amended and
Restated Declaration of Trust of the REIT, as amended prior to such change in
control).

                  1.28. "CREG" shall mean Constellation Real Estate Group, Inc.,
which is the one hundred percent (100%) direct owner of CPI and a guarantor
under certain indebtedness of the Sellers.

                                       5
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                  1.29. "Damage" shall have the meaning set forth in Section 19.

                  1.30. "Delinquent Rents" shall have the meaning set forth in
Section 17.9.

                  1.31. "Development Management Agreement" shall have the
meaning set forth in Section 5.7.

                  1.32. "Development Projects Acquisition Agreements" shall have
the meaning set forth in Section 5.4.

                  1.33. "Disapproved Exception" shall have the meaning set forth
in Section 9.2.

                  1.34. "Eminent Domain" shall have the meaning set forth in
Section 19.

                  1.35. "Entities" shall mean the Entities identified on Exhibit
"Entities".

                  1.36. "Environmental Law(s)" shall have the meaning set forth
in Section 13.1.1.

                  1.37. "Environmental Permits" shall have the meaning set forth
in Section 13.1.2.

                  1.38. "Escrowee" shall mean the Title Company.

                  1.39. "Estoppel Certificate" shall have the meaning set forth
in Section 15.2 of this Agreement.

                  1.40. "Existing Loan Documents" shall mean the Assumed
Loan Documents and the Satisfied Loan Documents.

                  1.41. "First Closing" shall have the meaning set forth in 
Section 6.1.

                  1.42. "First Closing Date" shall have the meaning set forth in
Section 6.1.

                  1.43. "Governmental Authority/Authorities" shall mean any
agency, commission, department or body of any municipal, township, county,
local, state or Federal governmental or quasi-governmental regulatory unit,
entity or authority having jurisdiction or authority over all or any portion of
the Projects or the management, operation, use or improvement thereof.

                  1.44. "Hazardous Conditions" shall have the meaning set
forth in Section 13.1.3.

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                  1.45. "Hazardous Material(s)" shall have the meaning set forth
in Section 13.1.4.

                  1.46. "Improvements" shall have the meaning set forth in the
recitals to this Agreement.

                  1.47. "Informational Materials" shall have the meaning set
forth in Section 11.1.8 below.

                  1.48. "Intangible Personal Property" shall have the meaning
set forth in the recitals to this Agreement.

                  1.49. "Interests" shall have the meaning set forth in the
recitals to this Agreement.

                  1.50. "Inventory" shall have the meaning set forth in the
recitals to this Agreement.

                  1.51. "Investor Materials" shall have the meaning set forth in
Section 4.1.3.

                  1.52. "Land" shall have the meaning set forth in the recital
to this Agreement.

                  1.53. "Leases" shall have the meaning set forth in the
recitals to this Agreement.

                  1.54. "Lenders' Approvals" shall have the meaning set forth in
Section 14.1.5.

                  1.55. "Letter of Credit" shall have the meaning set forth in
Section 6.3.

                  1.56. "Losses" shall have the meaning set forth in Section
13.3.

                  1.57. "NBP 135" shall mean the Entity identified as NBP 135 on
Exhibit "Entities" which owns the Project identified as 135 National Business
Park on Exhibit "Projects".

                  1.58. "NBP 135 Gross Value" shall have the meaning set forth
in Section 3.1.

                  1.59. "NBP 135 Sellers" shall mean those Sellers who are
selling all of the Interests in NBP 135.

                                       7

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                  1.60. "NBP 135 Lease Achievement Date" shall have the meaning
set forth in Section 6.2.1 of this Agreement.

                  1.61. "NBP 135/Woodlands Closing" shall have the meaning set
forth in Section 6.2.

                  1.62. "NBP 135/Woodlands Closing Date" shall have the meaning
set forth in Section 6.2.

                  1.63. "Net Asset Value" shall have the meaning set forth in
Section 3.1.

                  1.64. "Net Value Percentage Allocation" shall mean the
percentage assigned to each Project on Exhibit "Net Value Percentage
Allocation", the total percentage of which is one hundred percent (100%). Shares
shall be allocated among the Projects by multiplying the Net Asset Value by the
Net Value Percentage Allocation of each Project.

                  1.65. "NOI" shall have the meaning set forth in Section 3.2.

                  1.66. "Notice of Dispute" shall have the meaning set forth i
Section 6.3.

                  1.67. "Notice of Objection" shall have the meaning set forth
at Section 6.3.

                  1.68. "Option Projects" shall have the meaning set forth in
Section 5.5.

                  1.69. "Option/ROFR Agreements" shall have the meaning set
forth in Section 5.5.

                  1.70. "Permitted Exceptions" shall have the meaning set forth 
in Section 9.2.

                  1.71. "Personal Property" shall have the meaning set forth in
the recitals to this Agreement.

                  1.72. "Post-Closing Seller" shall have the meaning set forth
in Section 13.3.

                  1.73. "Preferred Share Amount" shall have the meaning set
forth in Section 3.2.2.

                  1.74. "Projects" shall have the meaning set forth in the
recitals to this Agreement.

                  1.75. "Proxy Statement" shall have the meaning set forth in
Section 4.5.

                  1.76. "Records" shall mean all books, records, tax returns,
correspondence, financial data, leases, and all other documents and matters,
public or private, maintained by

                                       8

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the Entities, the Sellers or its or their agents, relating to receipts and
expenditures pertaining to all of the Projects for the three most recent ful
calendar years and the current calendar year and all contracts, rental
agreements and all other documents and matters, public or private, maintained 
by the Entities, the Sellers or its or their agents, relating to operations
of the Projects.

                  1.77. "Registration Rights Agreement" shall mean the
Registration Rights Agreement in favor of the Sellers to be entered into by the
REIT at Closing in the form attached hereto as Exhibit "Registration Rights
Agreement".

                  1.78. "Regulatory Violation Notice" shall have the meaning
set forth in Section 4.1.3.

                  1.79. "REIT" means Corporate Office Properties Trust, a
Maryland real estate investment trust, which is the sole general partner of
Corporate Office Properties, L.P.

                  1.80. "Release" shall have the meaning set forth in Section 
13.1.5.

                  1.81. "Remedial Action" shall have the meaning set forth in
Section 13.1.6.

                  1.82. "Remedial Costs" shall have the meaning set forth in
Section 13.1.7.

                  1.83. "Satisfied Indebtedness" shall mean the outstanding
principal balance as of the Closing Date of the indebtedness of those Entities
identified on Exhibit "Satisfied Indebtedness" with respect to those Projects
identified on Exhibit "Satisfied Indebtedness" as such indebtedness is described
(including a statement of the outstanding principal balance as of the date of
this Agreement) on Exhibit "Satisfied Indebtedness". The Satisfied Indebtedness
is evidenced and secured by the Satisfied Loan Documents described on Exhibit
"Satisfied Loan Documents". Buyer, in Buyer's sole discretion, shall have the
right to assume any portion of the Satisfied Indebtedness, provided, however,
that as to any such assumed portion, the Entities, Sellers and CREG, as
applicable, obligated under such assumed portion are released from all
obligations under such assumed portion. If Buyer, in Buyer's sole discretion,
elects to assume any portion of the Satisfied Indebtedness, such portion shall
become part of the Assumed Indebtedness, and the amount of Satisfied
Indebtedness shall be reduced by an amount equal to the amount of the
outstanding principal of such assumed portion as of the Closing Date.

                  1.84. "Satisfied Loan Documents" shall mean the documents
evidencing or securing the Satisfied Indebtedness.

                  1.85. "SEC" shall mean the Securities and Exchange Commission.

                  1.86. "Securities Act" shall mean the Securities Act of 1933,
as amended.

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                  1.87. "Sellers" shall mean those persons and entities listed
as Sellers on the signature page to this Agreement and listed on Exhibit
"Sellers" .

                  1.88. "Sellers' Condition Precedent" shall mean all conditions
precedent to Seller's obligations to close as set forth in this Agreement.

                  1.89. "Seller Indemnified Parties" shall have the meaning set
forth in Section 20.4 of this Agreement.

                  1.90. "Service Company Agreement" shall have the meaning set 
forth at Section 5.3.

                  1.91. "Shares" shall mean collectively Common Shares and 
Convertible Preferred Shares.

                  1.92. "Tank(s)" shall have the meaning set forth in Section 
13.1.9.

                  1.93. "Taxes" shall have the meaning set forth in Section
11.1.4(b).

                  1.94. "Tax Returns" shall have the meaning set forth in
Section 11.1.4(b).

                  1.95. "Tenants" shall have the meaning set forth in Section
15.1.

                  1.96. "TIF  Agreement" shall have the meaning set forth in 
Section 5.8.

                  1.97. "Title Company" shall mean Commonwealth Land Title
Insurance Company.

                  1.98. "Title Reports" shall have the meaning set forth in
Section 9.2.

                  1.99. "Tred Avon" shall mean Tred Lightly Limited Liability
Company, a Maryland limited liability company, which is the holder of the Tred
Avon Loan Documents.

                 1.100. "Tred Avon Loan Documents" shall mean the notes, deeds
of trust encumbering the Project identified as Tred Avon on Exhibit "Projects",
and other loan documents described on Exhibit "Tred Avon Loan Documents"
evidencing and securing first and second deed of trust loans in the aggregate
original principal amount of $10,000,000.00 from TA Associates Limited
Partnership, a Maryland limited partnership, the owner of Tred Avon, to Tred
Avon.

                 1.101. "Woodlands" shall mean the Entity identified as
Woodlands on Exhibit "Entities" which owns the Project identified as Woodlands I
on Exhibit "Projects".

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<PAGE>

                 1.102. "Woodlands Gross Value" shall have the meaning set
forth in Section 3.1.

                 1.103. "Woodlands Lease Achievement Date" should have the
meaning set forth in Section 6.2.2.

                 1.104. "Woodlands Sellers" shall mean those Sellers who are 
selling all of the Interests in Woodlands.

         2.       ASSIGNMENT AND TRANSFER OF INTERESTS.

                  2.1. At Closing, each Seller agrees to assign and transfer to
Buyer, and Buyer agrees to accept and take from each Seller, on the terms and
conditions set forth in this Agreement, all of such Seller's right, title and
interest in the Interests, and CPI agrees to convey to Buyer and Buyer agrees to
accept, CPI's fee simple title interest in Brandon.

         3.       CONSIDERATION.

         Calculations under this Section 3 shall be computed separately for the
First Closing with all Sellers, other than the NBP 135 Sellers and the Woodlands
Sellers under Section 6.1, and for the NBP 135/Woodlands Closing with the
Woodlands Sellers and NBP 135 Sellers under Section 6.2 and, with respect to
each such Closing, shall relate only to those Sellers, Interests, and Projects
which are the subject of such Closing.

         In consideration of the assignment of the Interests to Buyer and
conveyance of Brandon to Buyer, and subject to the terms of this Agreement, at
Closing, the Buyer shall (a) pay to Sellers an amount equal to the Satisfied
Indebtedness (the "Cash Component"), (b) acquire the Interests and Brandon under
and subject to the Assumed Indebtedness and (c) deliver to the Sellers, Shares
(consisting of Seventy-Five percent (75%) Common Shares and Twenty-Five percent
(25%) Convertible Preferred Shares, as more particularly described in Section
3.2 below) having an aggregate value equal to the Net Asset Value (defined
below) of the Projects. Such consideration shall be referred to in this
Agreement as the "Consideration." The Shares issued to the Sellers at Closing
shall be issued to the respective Sellers in the same proportion as the
respective Sellers assign and convey Brandon and the Interests (subject to
appropriate rounding to eliminate fractional Shares), as more particularly
described on Exhibit "Share Schedule", as such allocation may be adjusted on the
updated Exhibit Share Schedule to be prepared by Buyer and to be mutually and
reasonably approved by Sellers and the Buyer at the Closing (the "Updated
Exhibit Share Schedule" or the "Share Schedule").

                  3.1. The "Net Asset Value" of the Projects (excluding NBP 135
and Woodlands) equals $142,550,000.00 [and as to NBP 135, $12,150,000.00 (the
"NBP 135 Gross Value"), and as to Woodlands, $17,600,000.00 (the "Woodlands
Gross Value"), both subject to adjustment as set forth in Section 3.2.5] less
the Cash Component, less the Assumed Indebtedness with respect to all Projects
(as such amount is reflected in the Exhibit "Assumed

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Indebtedness" on the Closing Date). The Net Asset Value shall be further
adjusted by the positive or negative adjustments and prorations described in 
Section 17 below, all of which shall be adjusted as of the Closing Date. The Net
Asset Value is allocated among the Projects in accordance with Exhibit "Net
Value Percentage Allocation".

                  3.2. The Consideration shall be determined, allocated and paid
by the Buyer to the Sellers at Closing as follows:

                  3.2.1. The Cash Component shall be allocated among, and paid
to the Sellers, in accordance with Exhibit "Cash Component Allocation".

                  3.2.2. Buyer shall acquire the Interests and Brandon subject
to the Assumed Indebtedness at the time of the Closing. Sellers acknowledge and
agree that the Sellers shall be solely responsible for any and all assumption
fees, transfer fees and other costs associated with the Buyer's acquisition of
the Interests subject to the Assumed Indebtedness and, in the event that the
holder of any existing financing on the Projects is unwilling to consent to the
transfer of the Interests, and Buyer elects to proceed to Closing, Sellers shall
be solely responsible for any prepayment penalties in connection the payment of
any such indebtedness.

                  3.2.3. Buyer shall deliver to Sellers Convertible Preferred
Shares ($25 par value per unit) having an aggregate value equal to Twenty-Five 
percent (25%) of the Net Asset Value of the Projects. This value expressed in 
dollars shall be referred to as the "Preferred Share Amount." Divide the
Preferred Share Amount by $25 (the par value of the Convertible Preferred 
Shares) to determine the number of Convertible Preferred Shares to be delivered.
If this calculation would result in a fractional number of Convertible Preferred
Shares to be delivered to Sellers, the Buyer shall round that fraction up or
down, as the case may be, to the nearest whole number of Convertible Preferred
Shares. The Share Schedule shall establish the allocation of Convertible
Preferred Shares to each Seller.

                  3.2.4. Buyer shall deliver Common Shares having an aggregate
value equal to Seventy-Five percent (75%) of the Net Asset Value of the 
Projects. This value expressed in dollars shall be referred to as the "Common
Share Amount". Divide the Common Share Amount by $10.50 to arrive at the number
of Common Shares to be delivered. If this calculation would result in a 
fractional number of Common Shares to be delivered to Seller, the Buyer shall
round that fraction up or down, as the case may be, to the nearest whole number 
of Common Shares. The Share Schedule shall establish the allocation of Common 
Shares to each Seller.

                  3.2.5. The NBP 135 Gross Value shall be decreased if the NOI
(defined below) of NBP 135 at the time of the NBP 135/Woodlands Closing is less
than $1,071,807. The Woodlands Gross Value shall be decreased if the NOI for
Woodlands at the time of the NBP 135/Woodlands Closing is less than $1,364,531.
If the NOI of NBP 135 is less than $1,071,807 at the time of the NBP 
135/Woodlands Closing, the NBP 135 Gross Value shall 

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equal the NOI of NBP 135 at the time of the NBP 135/Woodlands Closing divided by
a capitalization rate of 8.82%. If the NOI of Woodlands is less than $1,364,531
at the time of the NBP 135/Woodlands Closing, the Woodlands Gross Value shall
equal the NOI of Woodlands at the time of the NBP 135/Woodlands Closing divided
by the capitalization rate of 7.75%. "NOI" means the net operating income for a
Project determined as customarily calculated in the commercial real estate
industry for Projects similar to the Project for which the determination is
being made, based on the annualized operating revenues to be received from the
Project from Leases in effect (with Tenants paying rent) ten (10) days before 
the NBP 135/Woodlands Closing Date less the estimated annual operating expenses,
including, without limitation, a management fee of three and one-half percent 
(3.5%) of revenues, a structural reserve equal to $.20 per square foot of the 
Project, and a vacancy reserve of five percent (5%) of the number of square feet
of the Project times the anticipated average rent per square foot for the
Project.

                  3.2.6. The number of Common Shares at any time held by the
Sellers, in the aggregate, shall not exceed forty-five percent (45%) of the
outstanding Common Shares of the REIT.

                  3.2.7.    Buyer's right to assume the Assumed Indebtedness is
subject to the condition that the Sellers and CREG, as applicable, are released
from their obligations under the Assumed Indebtedness. If, despite Buyer's
commercially reasonable efforts to have the Sellers and CREG released from thei
obligations under the Assumed Indebtedness, Buyer is unable to obtain such 
release as to Assumed Indebtedness relating to a specific Project, Buyer shall 
indemnify the Sellers and CREG, as applicable, obligated on the subject Assumed
Indebtedness with respect to the deleted Project, and Sellers and CREG, as 
applicable, shall accept such indemnification by Buyer in lieu of a release.

                                       13

<PAGE>

         4.      SHARES; INVESTOR MATERIALS; PROXY STATEMENT.

                 4.1.1.  Investor Materials.  Each Seller, on or before ten (10)
days after the date of this Agreement, shall complete a questionnaire (in
substantially the form set forth in Exhibit "Investor Materials" attached
hereto, the "Investor Materials") providing, among other things, information
concerning each Seller's status as an Accredited Investor, and shall provide or
cause to be provided to Buyer, or to any other party designated by Buyer, such
other information and documentation as may reasonably be requested by Buyer in
furtherance of the issuance of the Shares as contemplated hereby.
Notwithstanding anything contained in this Agreement to the contrary, in the
event that, in the reasonable opinion of Buyer, based on advice of its 
securities counsel, (x) any such person or entity providing Investor Materials 
is not considered an Accredited Investor, (y) the proposed delivery of Shares
hereunder might not qualify for the exemption from the registration requirements
of Section 5 of the Securities Act, or (z) the proposed delivery of Shares
hereunder would violate any applicable federal or state securities laws, rules
or regulations, or agreements to which the REIT or the Buyer is a party, or any
tax related or other legal rules, agreements or constraints applicable to Buyer
or the REIT, Buyer shall so advise Seller, in writing (the "Regulatory Violation
Notice") within five (5) business days after such determination is made. In the
event a Regulatory Violation Notice is delivered, this Agreement shall terminate
and no party shall have any further liability hereunder except (i) as otherwise
expressly set forth in this Agreement and (ii) to the extent a breach of this
Agreement gives rise to, or becomes the basis for, the Regulatory Violation
Notice.

                  4.2. Certain Informational Materials. Sellers have been
furnished with the informational materials listed on Exhibit "Informational
Materials"). Sellers have read, reviewed and understand the Informational
Materials, and have been afforded the opportunity to ask questions of those
persons it considers appropriate and to obtain any additional information it
desires in respect of the Shares and the business, operations, conditions
(financial and otherwise) and current prospects of the COPLP and the REIT.
Sellers consulted their own financial, legal and tax advisors with respect to
the economic, legal and tax consequences of delivery of the Shares and have not
relied on the Informational Materials, COPLP, the REIT or any of their officers,
directors, affiliates or professional advisors for such advice as to such
consequences. Notwithstanding anything to the contrary contained in this Section
4.2, the effect of any representations or warranties expressly made by COPLP and
the REIT in this Agreement shall not be diminished, abrogated or compromised by
this Section 4.2.

                  4.3. Transfer Requirements. Sellers may only sell, transfer,
assign, pledge or encumber, or otherwise convey any or all of the Shares, in
strict compliance with the charter documents of the REIT, the registration and
other provisions of the Securities Act (and the rules promulgated thereunder),
any state securities laws, and the Registration Rights Agreement, in each case
as may be applicable. The provisions of this Section 4.3 shall survive the
Closing.

                                       14
<PAGE>
                  4.4. Registration Rights.  At the Closing, the REIT shall
execute and deliver the Registration Rights Agreement to the Sellers.

                  4.5. Proxy Statement. As promptly as practicable after the
execution of this Agreement, the REIT shall prepare and file with the SEC a
Proxy Statement (the "Proxy Statement") which shall solicit the votes of the
REIT's shareholders with respect to the transactions contemplated hereby. The
Proxy Statement shall include the recommendation of the REIT's Board of Trustees
in favor of this Agreement and the transactions contemplated hereby; provided,
however, that the Board of Trustees may modify or withdraw such recommendation
if it believes in good faith after consultation with legal counsel that the
modification or withdrawal of such recommendation is necessary for the Board to
comply with its fiduciary obligations under applicable law.

         5.        REIT BOARD OF TRUSTEES; CERTAIN REIT OPERATIONS;
 RELATED TRANSACTIONS.

                  5.1. Composition of REIT Board of Trustees. The REIT hereby
agrees that the Proxy Statement will include, as a part of the transaction
recommended to, and to be voted upon by the REIT's shareholders, an arrangement
reasonably satisfactory to Sellers and the REIT whereby immediately following
Closing, Sellers shall have the right to have two representatives of the Sellers
(each, a "Seller Representative") serve as members of the Board of Trustees of
the REIT (the "Board") for as long as Sellers are the owners, in the aggregate,
of more than thirty percent (30%) of the REIT's outstanding Common Shares, and
to have one Seller Representative serve as a member of the Board for as long as
Sellers are the owners, in the aggregate, of less than thirty percent (30%) but
more than fifteen percent (15%) of the REIT's outstanding Common Shares. The
initial Seller Representatives shall be designated by Sellers to the REIT prior
to the filing of the Proxy Statement. The principal terms of the arrangement
shall be as follows. At Closing, the number of members of the Board shall be
increased by two pursuant to Article III, Section 2 of the Bylaws of the REIT,
and the two initial Seller Representatives shall be appointed to the Board
pursuant to Article III, Section 10 of the Bylaws of the REIT. One Seller
Representative shall be appointed for a three-year term, and the other Seller
Representative shall be appointed for a two-year term.  Such Seller
Representatives shall serve the foregoing terms without regard to the 
percentage of Common Shares owned by Sellers, notwithstanding the first 
sentence of Section 5.1.  One Seller Representative shall be appointed to the
Investment Committee of the Board and each Seller Representative shall be 
eligible for appointment to other committees of the Board. Appropriate provision
shall be made to assure that Sellers shall have the right to designate a
replacement for a Seller Representative in the event of the death, resignation 
or removal of such person, and for a change in the number of Board members or
otherwise to assure continued representation on the Board by the Seller
Representative(s) in the event a Seller Representative who has been
nominated for election is not re-elected at a time when the Sellers are entitled
to have the Board representation described herein. For purposes of calculating
the percentages of Common Shares outstanding and owned by the Sellers, it shall
be assumed that any Convertible Preferred Shares then owned by the Sellers have
been converted into Common Shares and that such Common Shares are outstanding
and owned by the Sellers.

                                       15
<PAGE>

                  5.2. REIT Offices. From and after Closing, the REIT shall
maintain offices in Columbia, Maryland and in the Philadelphia, Pennsylvania
vicinity at such locations as the officers of the REIT shall elect. Initially,
general real estate operations shall be headquartered in the Columbia, Maryland
office of the REIT, and capital markets and acquisitions activities of the REIT
shall be headquartered in the Philadelphia, Pennsylvania office of the REIT.

                  5.3. Service Company Agreement. Concurrently with the
execution of this Agreement, Buyer and Constellation Real Estate, Inc. ("CREI"),
an affiliate of the Sellers, are entering into an agreement for the acquisition
by Buyer, or its Affiliate, of certain of the assets of CREI, including, without
limitation, tangible and intangible assets, and the Seventy-Five percent (75%)
interest of CREI in Constellation Realty Management LLC (the "Service Company
Agreement") for a purchase price of $2,500,000 payable in Shares. Closing under
the Service Company Agreement is to occur immediately after and on the same day
as Closing under this Agreement. The obligations of Sellers and Buyer to
complete Closing under this Agreement are subject to the completion of closing
under the Service Company Agreement.

                  5.4. Development Projects. Promptly following the execution of
this Agreement, Buyer and affiliates of the Sellers and other entities shall
negotiate in good faith to enter into two (2) acquisition agreements (the
"Development Projects Acquisition Agreements") for the acquisition by Buyer of
Interests in entities owning development projects in Maryland and Virginia as
will be more particularly described in the Development Projects Acquisition
Agreements. The Development Projects Acquisition Agreements will provide, among
other things, that they shall become effective among the parties thereto upon
the completion of Closing under Section 6.1 of this Agreement.

                  5.5. Option Projects. Concurrently with the execution of this
Agreement, Buyer and affiliates of the Sellers are entering into two (2) option
agreements with respect to the properties known as Lot 11 of the National
Business Park and Woodlands Two. At Closing, Buyer and the entities owning one
hundred percent (100%) of the interests (except as to the Option Project
identified as "Annapolis Exchange" on Exhibit "Option Projects") in the owners
of the Projects listed on Exhibit "Option Projects" (the "Option Projects"), as
the case may be, are entering into option agreements or option and right of
first refusal agreements (the "Option/ROFR Agreements"), granting to Buyer the
option to acquire one hundred percent (100%) of the interests in the entities
owing such Option Projects and fifty percent (50%) of the interests in Annapolis
Exchange.

                  5.6. Constellation Lease. At Closing, St. Barnabas Limited
Partnership, a Maryland limited partnership, the Entity owing the Project
identified as One Constellation Centre on Exhibit "Projects" and CPI shall enter
into a lease for CPI's leasing of approximately 48,863 square feet in One
Constellation Centre at a rent of $18.50 per square foot for two (2) years in
accordance with the terms of Exhibit "Constellation Lease" ("Constellation
Lease").

                                       16
<PAGE>

                  5.7. Development Management Agreement. At Closing, Buyer or an
Affiliate of Buyer, as Buyer shall elect, and CPI shall enter into a management
services agreement pursuant to which Buyer, or Buyer's Affiliate, shall provide
management services to CPI with respect to CPI's post-Closing real estate
portfolio for an eighteen (18) month period after Closing and shall receive the
following compensation: (a) from the Closing Date through the last day of the
third month after the Closing Date, $250,000.00 per month; (b) from the
first day of the fourth month after the Closing Date through the last
day of the sixth month after the Closing Date, $150,000.00 per month;
(c) from the first day of the seventh month after the Closing Date
through the last day of the tenth month following the Closing Date,
$100,000.00 per month, and; (d) from the first day of the eleventh
month following the Closing Date through the last day of the eighteenth 
month following the Closing Date, $50,000.00 per month (the "Development
Management Agreement"). The Development Management Agreement shall be
substantially in form of Exhibit "Development Management Agreement".

                  5.8. TIF Indemnification Agreement. Buyer and CPI shall enter
into an indemnification agreement substantially in the form of the
Indemnification Agreement attached hereto as Exhibit "TIF Indemnification
Agreement" (the "TIF Agreement") for CPI's indemnification of Buyer for certain
tax increases relating to the special tax district and the tax incremental
financing affecting the Projects located in the National Business Park, Anne
Arundel County, Maryland.

         6.        CLOSING.

                  6.1. First Closing. The assignment and transfer of the
Interests, the conveyance of Brandon, and the other transactions contemplated
herein with respect to all Sellers except the NBP 135 Sellers and the Woodlands
Sellers (the "First Closing") shall be consummated on the date (the "First
Closing Date"), after the shareholders of the REIT have approved all of the
transactions contemplated by this Agreement, specified by Buyer on not less than
seven (7) days notice to Sellers (the "Buyer's Closing Notice"), provided that
the First Closing Date shall not be sooner than July 1, 1998 or later than
thirty (30) days after the shareholders of the REIT have approved all of the
transactions contemplated by this Agreement. Sellers shall have the right to
postpone the First Closing to a date that is up to five (5) days after the First
Closing Date specified in Buyer's Closing Notice by giving Buyer notice of such
postponement. If the shareholders of the REIT have not approved the transactions
contemplated by this Agreement by October 30, 1998, this Agreement shall
terminate and become null and void, the Letter of Credit shall be returned to
the Buyer, and the parties shall be released from all liability or obligation to
the other. The Closing shall take place at the offices of Saul, Ewing, Remick &
Saul LLP, Centre Square West, 1500 Market Street, 38th Floor, Philadelphia,
Pennsylvania 19102, or at such other place as may mutually agreed upon by the
parties.

                  6.2. NBP 135/Woodlands Closing.

                                       17
<PAGE>


                  6.2.1. The assignment and transfer of the Interests in NBP 135
and the other transactions contemplated herein with respect to the NBP 135
Sellers (the "NBP 135 Closing"), shall occur after the First Closing under 
Section 6.1 of this Agreement, on the date (the "NBP 135 Closing Date") within
thirty (30) days after the "NBP 135 Lease Achievement Date" (defined below)
specified by Buyer on not less than seven (7) days notice to Sellers, but not 
later than December 31, 1998. As used in this Section 6.2.1, "NBP 135 Lease
Achievement Date", shall mean the date on which at least ninety-five percent 
(95%) of the rentable area of NBP 135 has been leased to Tenants who or which
have entered into Leases in accordance with Section 12.1 of this Agreement and 
have commenced paying rent under such Leases.

                  6.2.2. The assignment and transfer of the Interests in
Woodlands and the other transactions contemplated herein with respect to
Woodlands (the "Woodlands Closing", which shall occur after the First Closing
under Section 6.1 of this Agreement on the date (the "Woodlands Closing Date")
within thirty (30) days after the "Woodlands Lease Achievement Date" (defined
below) specified by Buyer on not less than seven (7) days notice to Sellers, but
not later than December 31, 1998. As used in this Section 6.2.2, "Woodlands
Lease Achievement Date" shall mean the date on which at least ninety-five
percent (95%) of the rental area of Woodlands has been leased to Tenants who or
which have entered into Leases in accordance with Section 12.1 of this Agreement
and have commenced
paying rent under such Leases.

                  6.2.3. Sellers shall provide Buyer with detailed written
updates of  leasing activity, lease status, and occupancy and rent payment
levels at NBP 135 and Woodlands at least monthly until the NBP 135/Woodlands
Closing, shall permit Buyer to review and copy leasing information for NBP 135
and Woodlands, and shall give Buyer prompt notice of the date Sellers believe is
the Lease Achievement Date.

                  6.3. Letter of Credit. On or before thirty (30) days after the
date of this Agreement, Buyer shall deliver to the Title Company, as escrowee
(the "Escrowee"), a non-transferrable, irrevocable standby letter of credit in
the amount of Five Million Dollars ($5,000,000.00) (the "Letter of Credit")
issued by a bank selected by Buyer, naming the Escrowee as the Beneficiary, and
having an expiration date no sooner December 10, 1998. The Letter of Credit
shall provide that the Escrowee may present it for payment only after Escrowee
receives a Certification of Default. The Letter of Credit shall be returned to
Buyer (a) upon Closing, or, (b) within fifteen (15) days after Buyer's request
by simultaneous notice to Escrowee and Sellers ("Buyer's Request"), upon
termination of this Agreement by Buyer under any Section of this Agreement
giving Buyer the right to so terminate (provided that Buyer is not in default
hereunder), or if for any reason other than the default of Buyer, Closing is not
completed under this Agreement, unless Sellers dispute the return of the Letter
of Credit to Buyer by notice of dispute to Escrowee and Buyer (the "Notice of
Dispute") given within ten (10) days after Buyer's Request. If the Escrowee
receives a Notice of Dispute, then the Escrowee shall continue to hold the
Letter of Credit until (a) the Escrowee receives a written notice signed by
Randall M. Griffin or John Harris Gurley, Esquire or

                                       18
<PAGE>

Charles E. Garman or Dan R. Skowronski and Buyer, directing the delivery of the
Letter of Credit, or (b) a final order of court of competent jurisdiction is
entered in a proceeding in which all Sellers and the Buyer are named as parties,
directing the delivery of the Letter of Credit in either of which events
described in clause (a) or clause (b), the Escrowee shall deliver the Letter of
Credit in accordance with such direction.

                  6.3.1.  Upon delivery by Sellers to Escrowee of a notarized 
default certificate signed by Randall M. Griffin or John Harris Gurley, Esquire
or Charles E. Garman or Dan R. Skowronski certifying that Buyer has defaulted in
the performance of Buyer's obligations under this Agreement and specifying the
alleged default in the form of Exhibit "Certification of Default" (the 
"Certification of Default"), Escrowee shall promptly submit a draft on the
Letter of Credit to the issuing bank. Escrowee shall then hold the proceeds from
negotiation of the Letter of Credit (the "Proceeds") in escrow and shall deposit
the Proceeds in a separate, interest-bearing money market account in a Federally
insured bank.

                  6.3.2. Promptly following receipt of the Certification of 
Default, Escrowee shall send a copy thereof to Buyer. If the Escrowee does not
receive from the Buyer written notice of objection (the "Notice of Objection")
to the Certification of Default within fifteen (15) days after the date of
Buyer's receipt of Certification of Default, Escrowee, after the expiration of
such fifteen (15)day period, shall pay the Proceeds, together with all interest
accrued thereon, to the Sellers, which shall be retained by the Sellers as 
liquidated damages for any default or breach by Buyer under this Agreement and
Sellers' sole and exclusive remedy against Buyer for any default or breach under
this Agreement. Upon receipt of a Notice of Objection from Buyer, the Escrowee 
shall promptly send a copy thereof to Sellers.

                 6.3.3. If the Escrowee receives a Notice of Objection from
Buyer within such fifteen (15) day period, then the Escrowee shall continue to
hold the Proceeds until (i) the Escrowee receives a written notice signed b
Randall M. Griffin or John Harris Gurley, Esquire or Charles E. Garman or Dan R.
Skowronski and Buyer, directing the disbursement of the Proceeds, or (ii) a
final order of court of competent jurisdiction is entered in a proceeding in
which all Sellers and the Buyer are named as parties, directing the disbursement
of the Proceeds, in either of which events described in clause (i) or clause
(ii), the Escrowee shall disburse the Proceeds in accordance with such
direction. If the Proceeds are paid to the Sellers pursuant to such direction,
the Proceeds shall be retained by Sellers as liquidated damages for any breach
or default by Buyer under this Agreement and as Sellers' sole and exclusive
remedy against Buyer for any breach or default under this Agreement. If the
Escrowee receives a Notice of Objection within the fifteen (15) day period set
forth above, the Escrowee shall have no liability by reason of its failure to
deliver the Proceeds to Sellers until the Escrowee has received the direction of
the nature described in clause (i) or clause (ii) above.

                 6.3.4. Sellers and Buyer agree that the Proceeds shall
constitute liquidated damages for any breach or default by Buyer of any Buyer's
obligations under this Agreement prior to the Closing Date or due to Buyer's
failure to complete Closing in

                                       19

<PAGE>

accordance with the terms of the Agreement, and that Sellers' receipt
of such Proceeds shall be Sellers' sole and exclusive remedy against Buyer for
any such breach or default by Buyer under this Agreement. This Section 6.3.4
shall not, however, be deemed to alter or impair any rights or remedies that
Sellers may have under this Agreement after Closing has been completed.

                 6.3.5. The Escrowee may act upon any instrument or other
writing believed by Escrowee in good faith to be genuine and to be signed and
presented by the proper person, and shall not be liable in connection with the
performance of any duties imposed upon the Escrowee by the provisions of this
Agreement, except for the Escrowee's own willful default or gross negligence. 
The Escrowee shall have no duties or responsibilities except those set forth in
this Agreement, unless the same is in writing and signed by Buyer and Randall M.
Griffin or John Harris Gurley, Esquire or Charles E. Garman or Dan R. Skowronski
on behalf of Sellers. Buyer and Sellers shall jointly and severally indemnify
and hold Escrowee harmless from and against all costs, claims, and expenses, 
including reasonable attorneys' fees, relating to the performance of Escrowee of
Escrowee's obligations under this Agreement, except with respect to Escrowee's
willful default or gross negligence. The Escrowee shall have the right to 
continue to hold the Letter of Credit if there is any dispute between the 
parties regarding delivery of the Letter of Credit. The Escrowee shall have the 
right to pay the Proceeds into court of competent jurisdiction if there is any
dispute between the parties regarding the payment of the Proceeds.

         7.        SELLER'S DELIVERIES.

         To the extent in any Seller's possession or control, each Seller shall
continue to make available to Buyer, from and after the Contract Date, at
reasonable times and upon reasonable notice, all documents, contracts,
information, Records and exhibits pertinent to the transaction that is the
subject of this Agreement, including, but not limited to, the documents listed
as "Seller's Deliveries" on Exhibit "Seller's Deliveries" attached hereto.

         8.        INSPECTION PERIOD.

                  8.1. Project Inspection. At all times prior to the Closing,
including times following the Inspection Period, Buyer, its agents and
representatives shall be entitled to conduct an inspection of the Projects,
which will include the rights to: (i) enter upon the Land and Improvements, on
reasonable notice to Seller, to perform inspections and tests of any and all of
the Projects, including, but not limited to, inspection, evaluation and testing
of the heating, ventilation and air-conditioning systems and all components
thereof, all structural and mechanical systems within the Improvements,
including, but not limited to, sprinkler systems, power lines and panels, air
lines and compressors, automatic doors, tanks, pumps, plumbing and all
equipment, vehicles, and Personal Property; (ii) examine and copy any and all
Records; (iii) make investigations with regard to zoning, environmental
(including, but not limited to, an environmental assessment as specified in
Section 8.2, which includes, but is not limited to, an analysis of the presence
of any asbestos, chlordane, formaldehyde or other

                                       20
<PAGE>



Hazardous Material in, under or upon the Projects, or any underground storage
tanks on, or under, the Land), building, code, regulatory and other legal or
governmental requirements; (iv)make or obtain market studies and real estate tax
analyses; and (v) interview Tenants with respect to their current and
prospective occupancies. Without limitation of the foregoing, Buyer or its
designated independent or other accountants may audit the Operating Statements
(as defined in Exhibit "Seller's Deliveries" attached hereto), and Sellers shall
supply such documentation as Buyer or its accountants may reasonably request in
order to complete such audit. Notwithstanding anything to the contrary contained
in this Agreement, the effect of any representations, warranties or undertakings
made by Sellers in this Agreement shall not be diminished, abrogated, or 
compromised by the foregoing inspections, environmental assessments or other
tests or investigations made by Buyer.

                  8.2. Environmental Assessment. Buyer or Buyer's agent(s) shall
have the right to employ one or more environmental consultants or other
professional(s) to perform or complete such environmental inspections and
assessments of the Projects as Buyer deems necessary or desirable. Buyer and its
consultants shall also have the right to undertake or complete a technical
review of all documentation, reports, plans, studies and information in
possession or control of Sellers, or its past or present environmental
consultants, concerning or in any way related to the environmental condition of
the Projects. In order to facilitate the assessments and technical review, each
Seller shall extend its full cooperation (but without third party expense to
such Seller) to Buyer and its environmental consultants, including, without
limitation, providing access to all files and fully and completely answering all
questions.

                  8.3. Buyer's Undertaking. Buyer hereby covenants and agrees
that it shall cause all studies, investigations and inspections performed at the
Projects pursuant to this Section 8 to be performed in a manner that does not
materially or unreasonably disturb or disrupt the tenancies or business
operations of any of the Projects' Tenants. In the event that, as a result of
Buyer's exercise of its rights under Sections 8.1 and 8.2, physical damage
occurs to any or all of the Projects, then Buyer shall promptly repair such
damage, at Buyer's sole cost and expense, so as to return the Projects to
substantially the same condition as exists on the Contract Date. Buyer hereby
indemnifies, protects, defends and holds each Seller harmless from and against
any and all losses, damages, claims, causes of action, judgments, damages, costs
and expenses that such Seller actually suffers or incurs as a direct result of
any physical damage caused to, in, or at the Projects during the course of, or
as a result of, any or all of the studies, investigations and inspections that
Buyer elects to perform (or causes to be performed) pursuant to this Section 8.

                  8.4. Confidentiality. Each party agrees to maintain in
confidence, and not to disclose to Tenants or Tenants' employees, the
information contained in this Agreement or pertaining to the transaction
contemplated hereby and the information and data furnished or made available by
Sellers to Buyer, its agents and representatives in connection with Buyer's
investigation of the Projects and the transactions contemplated by this
Agreement; provided, however, that each party, its agents and representatives
may disclose such information and 

                                       21
<PAGE>


data (i) to such party's accountants, attorneys, existing or prospective
lenders, investment bankers, accountants, underwriters, ratings agencies, 
partners, consultants and other advisors in connection with the transactions
contemplated by this Agreement to the extent that such representatives 
reasonably need to know (in the disclosing party's reasonable discretion) such
information and data in order to assist, and perform services on behalf of, the
disclosing party; (ii) to the extent required by any applicable statute, law, 
regulation or Governmental Authority (including, but not limited to, Form 8-K
and other reports and filings required by the SEC and other regulatory entities,
as described in Exhibit "Securities Reporting Requirements" attached hereto) or
by the New York Stock Exchange in connection with the listing of the Conversion
Shares; (iii) in connection with any litigation that may arise between the
parties in connection with the transactions contemplated by this Agreement or
otherwise relating to the Projects or any of them; (iv) to the extent such
disclosure is required or appropriate in connection with any securities offering
or other capital markets or financing transaction undertaken by the REIT; (v) to
the extent such information and data become generally available to the public
other than as a result of disclosure by such party or its agents or 
representatives; and (vi) to the extent such information and data become
available to such party or its agents or representatives from a third party who,
insofar as is known to such party, is not subject to a confidentiality
obligation to the other party hereunder; and (vii) to the extent necessary in 
order to comply with each party's respective covenants, agreements and 
obligations under this Agreement. In the event the transactions contemplated by
this Agreement shall not be consummated, such confidentiality shall be
maintained indefinitely. Furthermore, Sellers and Buyer acknowledge that,
notwithstanding any contrary term of this Section 8.4, Buyer shall have the
right to conduct Tenant interviews during the Inspection Period, and the
disclosure of the existence of this Agreement to the Tenants shall not
constitute a breach of the above restriction. Buyer shall also have the right to
issue a press release mutually acceptable to Buyer and Sellers upon the 
execution of this Agreement and consummation of the transactions described in 
this Agreement.

         9.        TITLE AND SURVEY MATTERS.

                  9.1. Title. At the Closing, Sellers agree that each Entity
(except Tred Avon) and Brandon shall have good and marketable fee simple title
to its Project(s), free and clear of all liens, claims and encumbrances except
for the Permitted Exceptions. From and after the date of this Agreement, Sellers
shall not take any action, or fail to take any action, that would cause title to
the Projects to be subject to any title exceptions or objections, other than the
Permitted Exceptions.

                  9.2. Title Commitments/Surveys. On or before thirty (30) days
after the Contract Date, Buyer shall furnish Sellers with a preliminary title
reports issued by the Title Company covering the Projects (the "Title Reports")
and a written notice specifying those title exceptions which are not acceptable
to Buyer in Buyer's commercially reasonable judgment, which objection may
include matters shown on any updated or re-certified survey which Buyer may
obtain (the "Disapproved Exceptions"). Buyer's failure to designate as one of
the Disapproved Exceptions a title exception shown on the Title Report shall
constitute Buyer's

                                       22
<PAGE>


approval of such title exception (all title exceptions not designated by Buyer 
as Disapproved Exceptions are in this Agreement called "Permitted Exceptions").
The applicable Seller(s) shall use their best efforts to cause the removal of
all Disapproved Exceptions on or before ten (10) days after Buyer's notice to
Seller of such Disapproved Exceptions, except that liens of an ascertainable
amount and other items which can be removed by the payment of money shall be
paid and discharged by Sellers at or before Closing. Within such ten (10) day
period, Seller(s) shall notify Buyer of all Disapproved Exceptions that
Seller(s), after using their best efforts, are unable to remove. Seller(s)'
failure to give Buyer notice of Seller(s)' inability to remove any
Disapproved Exceptions shall constitute such Seller(s)' covenant that such
Disapproved Exceptions shall be removed at or prior to the Closing. Buyer shall
have the rights set forth in Section 9.4 if any Disapproved Exceptions cannot be
removed by the applicable Seller(s) at or prior to the Closing.

                  9.3. It shall be an Buyer's Condition Precedent that the
marked-up Title Reports delivered on the Closing Date shall be in the form
described in this Section 9.3 and have all standard and general printed
exceptions deleted so as to afford full "extended form coverage," and shall
further include an owner's comprehensive endorsement, an endorsement certifying
that the bills for the real estate taxes pertaining to the Land and Improvements
do not include taxes pertaining to any other real estate; an access endorsement;
a contiguity endorsement, if applicable; a subdivision or plat act endorsement;
a survey endorsement; a non-imputation endorsement; a Fairway endorsement; and a
creditors' rights endorsement (if available).

                  9.4. If Sellers are unable to correct or remove any
Disapproved Exceptions in accordance with the requirements of this Section 9,
Buyer shall have the sole option of either (i) completing the Closing subject to
such Disapproved Exceptions without any abatement of the Consideration, except
that liens of an ascertainable amount and other items which can be removed by
payment of money shall be paid and discharged by Sellers or (ii) having the
Letter of Credit returned to Buyer and being immediately paid Buyer's Reasonable
Costs and, in the latter event, the parties shall be released from all liability
or obligation to the other and this Agreement shall then and thereafter be null
and void.

                  9.5. Tred Avon Loan Documents. At Closing, the Tred Avon Loan
Documents shall be free and clear of all liens, claims, encumbrances and
security interests of any nature, except the portion of the Assumed Indebtedness
held by Provident Bank of Maryland for which the Tred Avon Loan Documents are
security, and shall evidence and secure first and second deeds of trust as
described on Exhibit "Tred Avon Loan Documents" encumbering the Project
identified as Tred Avon on Exhibit "Projects".

                                       23
<PAGE>



         10.       REPRESENTATIONS AND WARRANTIES AS TO PROJECTS.

                  10.1. Sellers. The Sellers represent and warrant to Buyer, for
themselves and the Entities, that the following matters are true as of the
Contract Date and shall be true as of the Closing Date and covenant as follows:

                  10.1.1.   Title.  The Entities and CPI as to Brandon are the
legal fee simple titleholder of the Projects as more particularly described on
Exhibit "Projects", and, other than with respect to the Permitted Exceptions,
have, good, marketable and insurable title to the Projects, free and clear of
all mortgages and security interests (other than the Assumed Indebtedness and
Satisfied Indebtedness), leases, agreements and tenancies (other than the
Leases), licenses, claims, options, options to purchase, liens, covenants,
conditions, restrictions, rights-of-way, easements, judgments and other matters
affecting title to the Projects. The Projects are the only tangible assets owned
by the Entities. The sole business of each Entity is its ownership and operation
of the Project owned by it.

                  10.1.2.   Seller's Deliveries.  All of Seller's Deliveries
listed on Exhibit "Seller's Deliveries" attached hereto and all other items
delivered by Sellers pursuant to this Agreement are true, accurate, correct and
complete in all material respects, and fairly present the information set forth
in a manner that is not misleading. The copies of all documents and other
agreements delivered or furnished and made available by Sellers to Buyer
pursuant to this Agreement constitute all of and the only Leases and other
agreements relating to or affecting the ownership and operation of the Projects,
there being no material "side" or other agreements, written or oral, in force or
effect, to which any Seller or Entity is a party or to which the Project(s) 
is/are subject.

                10.1.3.  Defaults.  Neither the Entities nor any Seller is in
default under any of the documents, recorded or unrecorded, referred to in the
title commitments. To the knowledge of Sellers, there are no defaults under any
of the Major Repair Contracts, Contracts or Governmental Approvals (as such
terms are defined in Exhibit "Seller's Deliveries" attached hereto).

                10.1.4.  Contracts.  There are no contracts of any kind relating
to the management, leasing, operation, maintenance or repair of any Project,
except the Contract listed on Exhibit "Service Contracts" attached hereto.
Each Seller and each Entity has performed all material obligations required to 
be performed by it, and is not in default, under any of such Contracts. The
Contract may, by the express terms thereof be assigned to Buyer by notice to
such effect to the appropriate contract party, without penalty or other payment 
by Sellers, the Entities or Buyer.

                10.1.5.  Improvements.  The Improvements were completed and
installed in accordance with the Plans (as defined in Exhibit "Seller's
Deliveries" attached hereto), which were approved by all Governmental 
Authorities having jurisdiction thereover, and there

                                       24
<PAGE>


are not outstanding any notices of any material violation of any governmental
laws, ordinances, rules or regulations with respect to such Improvements.

                10.1.6.   Employees.  The Entities do not have any employees.

                10.1.7.   Compliance with Laws and Codes.  The Projects, and the
use and operation of any or all of them are (or the use and operation of any
component, portion or area of any Project is) in material compliance with
applicable municipal and other governmental laws, ordinances, regulations,codes,
licenses, permits and authorizations, and there are presently and validly in
effect all licenses, permits and other authorizations necessary (including,
without limitation, certificates of occupancy) for the use, occupancy and
operation of the Projects as they are presently being operated, whether required
of any Entity or any Tenant. Without limiting the foregoing, the Projects comply
in all material respects with all applicable requirements of the Americans With
Disabilities Act of 1990 (42 U.S.C.A. ss.12101 et seq.). The Projects are zoned 
by the municipality in which they are located so as to permit office and retail
uses and structures thereon, in a manner that accommodates and is fully
compatible with the Buildings and Improvements as they presently exist. No 
zoning, subdivision, environmental, Hazardous Material, building code, health,
fire, safety or other law, order or regulation is, or, on the Closing Date will 
be, violated by the continued maintenance, operation or use of any Improvements 
or parking areas in the Projects, and no notice of any such violation issued by
any Governmental Authority having jurisdiction over the Projects is outstanding.
All existing streets and other improvements, including water lines, sewer lines,
sidewalks, curbing and streets at each Project have been paid for and either
enter such Project through adjoining public streets, or, if they enter through
private lands, do so in accordance with valid, irrevocable easements running
with the ownership of such Project.

                10.1.8.  Litigation.  There are no pending (or to the best of 
each Seller's knowledge, threatened) judicial, municipal or administrative 
proceedings affecting any Entity or any Project, or in which any Seller is or
will be a party by reason of such Entity's ownership or operation of any Project
or any portion thereof, including, without limitation, proceedings for or 
involving collections, condemnation, eminent domain, alleged building code or
environmental or zoning violations, or personal injuries or property damage
alleged to have occurred on any Project or by reason of the condition, use of,
or operations on, such Project, except certain litigation to which CPI is a
party, but which is not material to the transfer of any Interests or Brandon by 
CPI and is not related to any Project. No attachments, execution proceedings,
assignments for the benefit of creditors, insolvency, bankruptcy, reorganization
or other proceedings are pending against any Entity, any Seller, or to the best
of Seller's knowledge, threatened against any Entity or any Seller, nor are any 
of such proceedings contemplated by any Entity or any Seller. In the event any
proceeding of the character described in this Section 10.1.8 is initiated or
threatened against any Entity or Seller prior to the Closing, Sellers shall
promptly advise Buyer thereof in writing, Sellers shall remain responsible
therefor, and Sellers shall indemnify, defend and hold Buyer from any claims,
losses, liabilities and expenses (excluding, without limitation, reasonable
counsel fees) relating to any such occurrence.

                                       25
<PAGE>



                10.1.9.   Insurance.  Each Entity or Seller now has in force
customary and commercially reasonable amounts of property, liability and
business interruption insurance relating to the Projects from established and
reputable insurers. No Entity or Seller has received any notice from any
insurance carrier, nor is any Entity or Seller aware of, any defects or
inadequacies in the Projects that, if not corrected, would result in termination
of insurance coverage or increase in the normal and customary cost thereof.

               10.1.10.  Financial Information.  All Operating Statements (as
defined in Exhibit "Seller's Deliveries" attached hereto) delivered by Sellers, 
and all of Sellers' and/or the Entities' Records, are complete, accurate, true
and correct, in all material respects; have been compiled in accordance with 
generally accepted accounting principles; and accurately set forth the results 
of the operation of the Projects and Entities for the periods covered. There has
been no material adverse change in the financial condition or operation of the
Projects and Entities since the period covered by the Operating Statements.

                10.1.11.  Re-Zoning.  There is not now pending, and neither any
Entity nor any Seller has knowledge of, any threatened proceeding for the
rezoning of any Project or any portion thereof, or the taking of any other
action by governmental authorities that would have any material adverse impact 
on the value of any Project or use thereof.

                10.1.12.  Real Estate Taxes.  True and complete copies of the 
mpst recent real estate "Tax Bill(s)" for (and the only real estate tax bills 
applicable to) the Projects have been delivered to Buyer. Except as set forth on
Exhibit "Real Estate Tax Matters" attached hereto, no Entity nor Seller has
received notice of and does not have any actual knowledge of any proposed
increase in the assessed valuation or rate of taxation of any or all of the
Projects from that reflected in the most recent Tax Bills. Except as described
on Exhibit "Real Estate Tax Matters" attached hereto, there is not now pending,
and no Entity will, without the prior written consent of Buyer, institute prior
to the Closing Date, any proceeding or application for a reduction in the real
estate tax assessment of any of the Projects or any other relief for any tax
year. There are no outstanding agreements with attorneys or consultants with
respect to the Tax Bills that will be binding on Buyer or any of the Projects
after the Closing, except for Constellation Centre as noted on Exhibit "Real 
Estate Tax Matters". Other than the amounts disclosed by the Tax Bills, no other
real estate taxes have been, or will be, assessed against the Projects, or any 
portion thereof, in respect of the year 1998 or any prior year, and no special 
assessments of any kind (special, bond or otherwise) are or have been levied 
against the Projects, or any portion thereof, that are outstanding or unpaid,
and, to the best of each Seller's knowledge, none will be levied prior to the
Closing. Each Entity has paid all real estate taxes presently due and owing with
respect to the Projects.

                10.1.13.  Easements and Other Agreements.  To the knowledge of
Sellers, no Entity or Seller is in default in complying with the terms and
provisions of any of

                                       26
<PAGE>



the covenants, conditions, restrictions, rights-of-way or easements constituting
one or more of the Permitted Exceptions.

                10.1.14.  Lease Controversies.  Except as described in Exhibit
"Lease Controversies" attached hereto, no material controversy, complaint,
negotiation or renegotiation, proceeding, suit or litigation relating to all or
any of the Leases, is pending or, to the knowledge of Sellers, threatened,
whether in any tribunal or informally. Sellers are and shall remain responsible
after the Closing Date for defending (or continuing) any such suit, proceeding
or other matter relating to periods prior to the Closing Date, and all damages,
loss, expenses and costs related thereto.

                10.1.15.  Existing Loan Documents.  Exhibits "Assumed Loan
Documents" and "Satisfied Loan Documents" set forth true, correct and complete
schedules of all of the notes, deeds of trust, and other loan documents
evidencing or securing the Assumed Indebtedness and Satisfied Indebtedness,
respectively. Sellers have delivered true, correct and complete copies of the
Existing Loan Documents to Buyer prior to the date hereof as part of the
Seller's Deliveries. Each Entity and Seller has complied with (and, prior to the
Closing, shall continue to comply with) the terms of, and all notices or 
correspondence received from the holders of, the Existing Loan Documents
Each Entity and/or Seller has paid (and, at all times prior to the Closing,
shall pay) all sums due under the Existing Loan Documents. No Entity or Seller 
shall make any prepayment of any amount due under the Loan Documents. The 
Existing Loan Documents are in full force and effect, and, to the best knowledge
of each Seller and each Entity, no Entity nor any Seller is in default 
thereunder, and there has not occurred any event which, with the giving of
notice and/or the passage of time, or both, would constitute a default by any 
Entity or Seller thereunder or under any of the Existing Loan Documents. The
outstanding principal balance under the Assumed Indebtedness as of the Contract
Date is $13,062,178 ($9,625,148.00 as to the Project known as Cranberry Square
and $3,457,030.00 secured by a security interest in the deed of trust
encumbering the Project known as Tred Avon.)

               10.1.16.  Tred Avon Loan Documents. Exhibit "Tred Avon Loan 
Documents" attached hereto sets forth a true, correct and complete schedule of
all of the notes, deeds of trust and the other loan documents evidencing or
securing the Tred Avon Indebtedness. Sellers have delivered true, correct and 
complete copies of the Tred Avon Loan Documents to Buyer prior to the date
hereof as part of the Seller's Deliveries. TA Associates Limited Partnership has
complied with the terms of, and all notices or correspondence received from the
holder of, the Tred Avon Loan Documents. TA Associates Limited Partnership has 
paid all sums due under the Tred Avon Loan Documents. The Tred Avon Loan
Documents are in full force and effect, and to the best knowledge of each Seller
and each Entity, TA Associates Limited Partnership is not in default thereunder,
and there has not occurred any event which, with the giving of notice and/or the
passage of time, or both, would constitute a default by TA Associates Limited
Partnership thereunder or under any of the Tred Avon Loan Documents. The 
outstanding principal balance under the Tred Avon Loan Documents on the Contract
Date is $9,659,512.00.

                                       27
<PAGE>


               10.1.17.  Condemnation. Sellers and the Entities have no
knowledge of any pending or contemplated condemnation or other governmental
taking proceedings affecting all or any part of any or all of the Projects.

               10.1.18.  Disclosure.  No representation or warranty made by any
Seller in this Agreement, no exhibit attached hereto with respect to the
Projects, and no schedule contained in this Agreement contains any untrue 
statement of a material fact, or omits to state a material fact necessary in 
order to make the statements contained therein not misleading. Except as 
otherwise expressly set forth in this Agreement, Seller makes no representation
or warranty, express or implied, as to the physical condition of the Projects,
and Buyer is purchasing the Interests and Brandon with the Projects "AS-IS,
WHERE-IS" as to physical condition.

         The representations and warranties in this Section 10 shall be deemed
remade by each Seller as of the Closing Date with the same force and effect as
if in fact specifically remade at that time. The representations and warranties
made in this Section 10 shall survive the Closing for a period of eighteen (18)
months. Notwithstanding anything to the contrary herein, the effect of the
representations and warranties made in this Agreement by Sellers shall not be
diminished, abrogated or deemed to be waived by the inspections, assessments, or
any other investigations made by Buyer.

         11.    REPRESENTATIONS AS TO INTERESTS/SECURITIES AND RELATED MATTERS.

                  11.1. Sellers. The Sellers represent and warrant to Buyer that
the following matters are true as of the Contract Date and shall be true as of
the Closing Date and covenant as follows:

               11.1.1.  Authority.  Each Seller is duly formed, validly 
existing, and in good standing under the laws of Maryland, and has the power and
authority to own the Interests owned by it. The execution and delivery of this
Agreement by Sellers, and the performance of this Agreement by Sellers, have
been duly authorized by Sellers, respectively, and this Agreement is binding on
Sellers and enforceable against them in accordance with its terms. No consent of
any creditor, investor, partner, shareholder, tenant-in-common, judicial or
administrative body, Governmental Authority, or other governmental body or 
agency, or other party to such execution, delivery and performance by Sellers is
required. Neither the execution of this Agreement nor the consummation of the
transactions contemplated hereby will (i) result in a breach of, default under,
or acceleration of, any agreement to which Sellers are a party or by which 
Sellers, or the Projects are bound; or (ii) violate any restriction, court 
order, agreement or other legal obligation to which Sellers, and/or any of the
Projects are subject.

                                       28
<PAGE>


                 11.1.2.  Entities.  Each Entity is duly formed, validly 
existing, and in good standing under the laws of Maryland, and has the power and
authority to own its Project (or, as to Tred Avon, the Tred Avon Loan
Documents). Sellers have delivered to Buyer, as part of Sellers' Deliveries, all
of the documents relating to the formation or governance of the Entities. Each
Entity is a single purpose entity, organized for the sole purpose of owning its
Project (or as to Tred Avon, the Tred Avon Loan Documents).

                 11.1.3.   Interest.  The direct and indirect ownership of each
Seller including percentage interests of ownership, is as reflected on Exhibit
"Sellers". The Interests constitute one hundred percent (100%) of the Interests
in the Entities, except Tred Avon in which CPI owns a seventy-five percent (75%)
Interest. Each Seller owns the Interests owned by such Seller, as set forth on
Exhibit "Sellers" hereto, free and clear of all liens, charges, encumbrances,
restrictive agreements and assessments, other than restrictions on transfers and
other similar provisions as set forth in the relevant Partnership Agreement,
which such Seller warrants and represents shall not be violated by the
assignment of Interests contemplated by this Agreement. Upon the assignment of
such Seller's Interest to the Buyer (or its designee(s)), the Buyer will receive
good and absolute title thereto, free from all liens, charges, encumbrances,
restrictive agreements and assessments whatsoever, other than restrictions on
transfers and other similar provisions as set forth in the relevant Partnership
Agreement. Each Seller hereby waives, with respect to the assignment
contemplated by this Agreement, any "right of refusal" or other restriction on
transfer set forth in the Partnership Agreement of any Entity of which such
Seller is a partner. There are no outstanding options, contracts, calls,
commitments or demands of any nature relating to the Interests of any Seller.

                 11.1.4.  No Transfers of Interests.  There will be no changes
in the composition of any Entity between the date of this Agreement and Closing,
except for transfers by and between entities controlled by CPI ("CPI 
Affiliates"). Transfers of any Interests to CPI Affiliates shall be subject to
this Agreement, the transferor/assignor Sellers shall not be relieved of their 
obligations under this Agreement, and the CPI Affiliates which are transferees/
assignees of Interests shall become Sellers under this Agreement. Sellers shall
give Buyer written notice of such transfers to CPI Affiliates and shall provide 
Buyer with copies of all executed documents effecting such transfers.

                 11.1.5.   Tax-Related Issues.

                           (a)  Each Entity is, and at all times has been,
properly treated as a partnership for federal income tax purposes and not as an
"association" or "publicly traded partnership" taxable as a corporation.

                           (b)  Each Entity has filed or caused to be filed in a
timely manner (within any applicable extension periods) all tax, information or 
other returns required to be filed by the Code or by applicable state, or loca
tax laws (collectively, "Tax Returns"). Such Tax Returns are true, correct and 
complete in all respects; and all federal, state or local income, gross
receipts, license, payroll, employment, excise, severance, stamp, occupation,

                                       29

<PAGE>


premium, unemployment, disability, personal property, sales, use, transfer, 
registration, estimated, or other tax of any kind whatsoever, including any
interest, penalty or other addition thereto, whether disputed or not
(collectively, "Taxes") due, and Taxes due in respect of any person for which 
the applicable Entity had an obligation to withhold and/or otherwise pay over 
Taxes, have been timely paid in full or will be timely paid in full by the due
date thereof (and whether or not shown on a Tax Return). With respect to any
taxable year for which a statute of limitations (or similar provision) has not
yet run, none of the Tax Returns of the applicable Entity has been audited by a
government or taxing authority, nor is any such audit or other proceeding in 
process, pending, threatened (either in writing or verbally, formally or
informally) or expected to be asserted with respect to Taxes (or the collectio
of Taxes) of the applicable Entity, and no Entity has received notice (either
in writing or verbally, formally or informally) or expects to receive notice
that it has not filed a Tax Return or not paid Taxes required to be filed,
withheld, or paid by it. Each Entity has disclosed on its federal income tax 
returns all positions taken therein that could give rise to a substantial 
understatement penalty within the meaning of Code Section 6662. No claim has 
ever been made by an authority in a jurisdiction where such Entity does not
file Tax Returns that it is or may be subject to taxation by that jurisdiction.

                  11.1.6.  United States Person.  Each Entity and each Seller is
a "United States Person" within the meaning of Section 1445(f)(3) of the Code,
as amended, and shall execute and deliver an "Entity Transferor" certification
at Closing.

                  11.1.7.  Entity Liabilities.  Except for (i) the Assumed
Indebtedness, and (ii) any accrued liabilities and obligations of the Entities
that are being adjusted at the Closing pursuant to Section 17 of this Agreement,
the Entities shall not have any liabilities or obligations, either accrued,
absolute, contingent, or otherwise, which will not be paid or discharged on or
before the Closing Date.  In addition, except for the claims and liabilitie
described in the preceding sentence, neither the Sellers nor the Entities have
received notice of any claim against (or liability of) the Entities arising from
business done, transactions entered into or other events occurring prior to the
Closing Date (and to the best knowledge of the Sellers and the Entities,
no basis for any such claim or liability exists).

                  11.1.8.  Investment Representation.  Each Seller has such
knowledge and experience in financial and business matters so as to be fully
capable of evaluating the merits and risks of an investment in the Shares. No
Shares will be issued, delivered or distributed to any person or entity who
either (i) is a resident of the State of California or New York or (ii) is 
other than an Accredited Investor with respect to whom there has been delivered
to Buyer satisfactory Investor Materials confirming the status of such person or
entity as an Accredited Investor. Each Seller has been furnished with the
informational materials described in Section 4.2 above (collectively, the
"Informational Materials"), and has read and reviewed the Informational 
Materials and understands the contents thereof. The Sellers have been afforded 
the opportunity to ask questions of those persons they consider appropriate and 
to obtain any additional information they desire in respect of the Shares and
the business, operations, conditions (financial and otherwise) and current
prospects of the

                                       30

<PAGE>

Buyer and the REIT. The Sellers have consulted their own financial, legal and
tax advisors with respect to the economic, legal and tax consequences of
delivery of the Shares and have not relied on the Informational Materials,
Buyer, the Buyer, the REIT or any of their officers, directors, affiliates or
professional advisors for such advice as to such consequences. All of the
holders of interests in each Seller are Accredited Investors. No Seller
requires the consent of any interest holder in order to consummate the
transactions contemplated by this Agreement, including, without limitation,
to amend any partnership agreement, operating agreement, charter or other
governing document of such Seller. All of the Sellers are formed under the law 
of the State of Maryland, or as to natural individuals, are domiciled in the 
State of Maryland.

                 11.1.9.   The representations and warranties in this Section
11.1 shall be deemed remade by each Seller, as of the Closing Date with the same
force and effect as if specifically remade at that time. The representations and
warranties made in this Section 11.1 shall survive the Closing without
limitation.

            11.2. COPLP and the REIT. COPLP and the REIT represent and
warrant to Sellers that the following matters are true as of the Contract Date
and shall be true as of the Closing Date:

                 11.2.1.   COPLP is a limited partnership validly existing under
the laws of the State of Delaware and has all requisite power to carry on its
business as now conducted. The REIT is the sole general partner of COPLP and is
a duly formed and validly existing Maryland real estate investment trust. Each
of COPLP and the REIT has full power and authority and possesses all material
authorizations and approvals necessary to enable it to execute and deliver this
Agreement and the other documents to be executed by it pursuant to this 
Agreement, and perform its obligations hereunder and thereunder. This Agreement
and the other documents to be executed by COPLP and the REIT pursuant to this
Agreement when executed and delivered by COPLP and the REIT will, subject to 
approval by the shareholders of the REIT prior to Closing, constitute valid and
legally binding obligations of each of COPLP and the REIT, enforceable against 
them in accordance with their respective terms, subject to bankruptcy and 
insolvency laws, and to equitable principles which may be imposed by courts.

                 11.2.2.   Subject to approval by the shareholders of the REIT,
the execution, delivery and performance of this Agreement and the other
documents to be executed, delivered and performed pursuant to this Agreement do
not and will not (with or without the passage of time or the giving of notice):
(i) violate or conflict with COPLP's Partnership Agreement or the REIT's Amended
and Restated Declaration of Trust, or any law binding upon COPLP or the REIT; 
(ii) violate or conflict with, result in a breach of, or constitute a default or
otherwise cause any loss of benefit under, any agreement or other obligation to
which COPLP or the REIT is a party or by which either of them (or the assets of
either of them) is bound, or give to any other party any rights (including, 
without limitation, rights of termination, foreclosure, cancellation or 
acceleration) in, or with respect to COPLP

                                    31

<PAGE>


or the REIT; or (iii) result in, require, or permit the creation or imposition
of, any restriction, mortgage, deed of trust, pledge, lien, security interest or
other charge, claim or encumbrance upon, or with respect to, COPLP or the REIT
or the assets of either of them.

                11.2.3.   There are no actions, suits, claims, proceedings,
investigations or inspections, pending or (to the REIT's knowledge) threatened,
against or affecting COPLP or its Affiliates which could have a material adverse
affect on COPLP and its Affiliates considered as a whole, and to the REIT's
knowledge there are no matters of litigation or governmental proceedings 
expected to be brought against it or its Affiliates which could have a material
adverse affect on the financial condition of the REIT and its Affiliates 
considered as a whole.

                11.2.4.   No consent, order, approval or authorization of, or 
registration, declaration or filing with, any court, administrative agency o
commission or other governmental authority or agency, domestic or foreign, is 
required by or with respect to the COPLP or the REIT in connection with the
execution, delivery and perform nce of this Agreement and the other documents to
the executed, delivered and performed pursuant to this Agreement.

                11.2.5.   The Informational Materials did not, as of their
respective dates of filing, contain any untrue statement of a material fact o
omit to state a material fact required to be stated therein or necessary to make
the statements contained therein, in light of the circumstances under which they
were made, not misleading. There has not been any material adverse change in the
business of COPLP or the REIT since March 31, 1998. Except as may otherwise be
set forth therein, the financial statements (including the notes thereto) of the
REIT set forth in the Informational Materials present fairly the consolidated
financial position of the REIT as at the dates set forth therein and its results
of operations, changes in consolidated stockholder equity and cash flows for
periods covered thereby, all in conformity with United States generally accepted
accounting principles applied on a consistent basis for such periods.

                11.2.6.   The Shares to be issued at Closing will, when issued
and delivered, be duly authorized, validly issued, fully paid, non-assessable
shares of the REIT free from all claims of preemptive rights.

                11.2.7.   COPLP has been at all times, and presently intends to 
continue to be, classified as a partnership for federal income tax purposes and
not an association taxable as a corporation or a publicly traded partnership 
taxable as a corporation. The REIT is now, and presently intends to continue to
be classified, as a real estate investment trust under Section 856 of the
Internal Revenue Code of 1986, as amended.

                11.2.8.   All documents and other papers delivered by or on
behalf of COPLP or the REIT in connection with the transactions contemplated by
this Agreement are accurate and complete in all material respects and are 
authentic. No representation or warranty of COPLP or the REIT contained in this
Agreement contains any untrue statement of

                                     32

<PAGE>


a material fact or omits to state a fact necessary in order to make the
statements herein or therein, in light of the circumstances under which they 
were made, not misleading. Except as
described in this Agreement or in the Informational Materials there is no fact 
known to COPLP or the REIT or (other than proposed or enacted legislation,
proposed or enacted regulation, or general economic or real estate industry 
conditions and changes) that materially adversely affects or, so far as COPLP
and the REIT can reasonably foresee, materially threatens, the assets, 
activities, prospects, financial condition or results of COPLP or the REIT.

                  11.2.9.   The representations and warranties in this Section
11.2 shall be deemed remade by COPLP and REIT as of the Closing Date with the
same force and effect as if remade at Closing. The representations and 
warranties made in this Section 11.2 shall survive Closing without limitation.

         12.      COVENANTS OF SELLER.

         Sellers (for themselves and for the Entities) hereby covenant with
Buyer as follows:

                  12.1. New Leases. Neither the Entities nor CPI as to Brandon
shall amend any Lease or execute any new lease, license, or other agreement
affecting the ownership or operation of all or any portion of the Projects or
for personal property, equipment, or vehicles, without Buyer's prior written
approval. The Tred Avon Loan Documents shall not be amended without the prior
written consent of Buyer. The Existing Loan Documents shall not be amended
without the prior written consent of Buyer. Buyer shall be deemed to have
consented to any document or action under Sections 12.1 or 12.2 for which
Sellers have requested approval by written request (specifying in such request
that Buyer must object, if at all, within five (5) days after receipt) to Buyer
if Buyer does not object to such document or action within five (5) days after
receiving such request from Sellers. No prepayment shall be made under any of
loans evidenced or secured by the Existing Loan Documents.

                  12.2. New Contracts. Neither the Entities nor CPI shall enter
into any contract with respect to the ownership and operation of all or any
portion of any or all of the Projects that will survive the Closing, or that
would otherwise affect the use, operation or enjoyment of any or all of the
Projects, without Buyer's prior written approval, except for service contracts
entered into in the ordinary course of business that are terminable, without
penalty, on not more than 30 days' notice, for which no consent shall be
required.

                  12.3. Insurance.  The insurance policies described in Section
10.1.11 above shall remain continuously in force through and including the 
Closing Date.

                  12.4. Operation of Projects. The Entities and CPI as to
Brandon shall operate and manage the Projects in a manner consistent with the
manner in which they are being operated on the Contract Date, maintaining the
current level of services, shall maintain the Projects in good repair and
working order; shall keep on hand sufficient materials, supplies,

  
                                       33

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equipment and other Personal Property for the efficient operation and management
of the Projects in a first class manner; and shall perform, when due, all of the
Entities' obligations under the Existing Loan Documents, Leases, Contracts,
Governmental Approvals and other agreements relating to the Projects and
otherwise in accordance with applicable laws, ordinances, rules and regulations
affecting the Projects. Except as otherwise specifically provided herein, the
Entities and CPI as to Brandon shall deliver the Projects at Closing in
substantially the same condition as each of them is in on the Contract Date,
reasonable wear and tear excepted. Sellers shall cause Tred Avon to the collect
the indebtedness under, and shall hold the Tred Avon Loan Documents in the
manner in which they are currently being collected and held. Sellers shall cause
the Entities to pay when due all amounts due under Existing Loan Documents and
to perform all obligations of such Entities under the Loan Documents.

                  12.5. Pre-Closing Expenses. Sellers have paid or will pay or
cause to be paid in full, prior to the Closing, all bills and invoices for
labor, goods, material and services of any kind relating to the Projects and
utility charges, relating to the period prior to the Closing. Except as the
parties may otherwise agree at or prior to Closing, any alterations,
installations, decorations and other work required to be performed under any and
all agreements affecting the Projects have been or will, by the Closing, be
completed and paid for in full.

                  12.6. Good Faith. All actions required pursuant to this
Agreement that are necessary to effectuate the transaction contemplated herein
will be taken promptly and in good faith by Sellers or the Entities, as
applicable, and each Seller shall furnish Buyer with such documents or further
assurances as Buyer may reasonably require.

                  12.7. No Assignment. After the Contract Date and prior to the
Closing, no Seller shall assign, alienate, lien, encumber or otherwise transfer
all or any part of any or all of the Interests, the Projects or any interest in
any or all of them, except for transfers of Interests to CPI Affiliates. Sellers
shall give Buyer notice of the transfers of any Interests to CPI Affiliates,
together with copies of the signed documents effecting such transfers.

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                  12.8. Availability of Records, Audit Representation Letter.

                        12.8.1. Upon Buyer's request, for a period of two
years after the Closing, Sellers shall (i) make the Records available to Buyer
for inspection, copying and audit by Buyer's designated accountants; and (ii)
cooperate with Buyer (without any third party expense to Sellers) in obtainin
any and all permits, licenses, authorizations, and other Governmental Approvals
necessary for the operation of any or all of the Projects. Without limitation of
the foregoing in this Section 12.8, Sellers agree to abide by the terms of
Exhibit "Securities Reporting Requirements" attached hereto. At any time before
or within two years after the Closing, Sellers further agree to provide to the
Buyer's designated independent auditor, upon request of Buyer or such auditor: 
(x) access (to the same extent to which Buyer would be entitled to such access)
to the books and records of the Projects and all related information (including
the information listed on Exhibit "Securities Reporting Requirements") regarding
the period for which Buyer is required to have the Project audited under the
regulations of the Securities and Exchange Commission, and (y) a representation
letter delivered by each managing agent of the Projects regarding the books and
records of the Projects, in substantially the form as attached hereto as Exhibit
"Audit Representation Letter".

                     12.8.2.  In addition, Sellers shall provide, and cooperate,
in all respects, in providing, Buyer with copies of, or access to, such factual
information as may be reasonably requested by Buyer, and in the possession or
control of Sellers, to enable the REIT to issue one or more mutually agreed upon
press releases concerning the transaction that is the subject of this Agreement,
to file a Current Report on Form 8-K (as specified on Exhibit "Securities 
Reporting Requirements" attached hereto), if, as and when such filing may be
required by the SEC and to make any other filings that may be required by any 
Governmental Authority. The obligation of Sellers to cooperate in providin
Buyer with such information for Buyer to file its Current Report on Form 8-K
shall survive the Closing.

                12.9. Change in Conditions. Sellers shall promptly notify
Buyer of any change in any condition with respect to any or all of the Entities,
the Projects or of the occurrence of any event or circumstance that makes any
representation or warranty of Sellers to Buyer under this Agreement untrue or
misleading, or any covenant of Buyer under this Agreement incapable or less
likely of being performed, it being understood that Sellers' obligation to
provide notice to Buyer under this Section 12.9 shall in no way relieve Sellers
of any liability for a breach by Sellers of any of its representations,
warranties or covenants under this Agreement.

                12.10. Entity Structure. Except for transfers of Interests to
CPI Affiliates, from the Contract Date through and including the Closing Date,
the Entities and Sellers shall maintain the same composition of its partners,
shareholders and members as the case may be, as exists on the Contract Date,
unless otherwise expressly or consented to by Buyer in writing.

                                       35

<PAGE>


                 12.11. Cure of Violations. On or before the Closing Date,
Sellers shall cure (or escrow sufficient funds at the Closing with the Title
Company to cure) (i) all violation(s) of law, code, ordinance or regulation that
are the subject of any written notice issued by a Governmental Authority with
respect to any Project, and (ii) legal deficiencies discovered at or in any
Project before the Closing.

                 12.12. Tenant Purchase Rights. Exhibit "Tenant Purchase
Rights" sets forth the purchase rights of three (3) Tenants as more particularly
described in Exhibit "Tenant Purchase Rights", a right of first option held by
Giant of Maryland, Inc. ("Giant") with respect to the Cranberry Square Project
(the "Giant Purchase Right"), an option to purchase held by the United States of
America with respect to the One National Business Park Project (the "USA
Purchase Right"), and a right of first refusal held by Green Spring Health
Services, Inc. with respect to the Woodlands I Project (the "Green Spring
Purchase Right").

                   12.12.1.  Buyer agrees to accept the One National Business
Park Project subject to the USA Purchase Right.

                   12.12.2.  Promptly after the Contract Date, Sellers shall
notify Giant of this transaction and the sale of the Interests of the Entity
owning the Cranberry Square Project. The obligation of Buyer to purchase the 
Interests of Entity owning Cranberry Square is contingent upon Giant's entering
into an agreement of sale to purchase the Cranberry Square Project on or before 
the Closing Date. If, prior to Closing, Giant enters into an agreement to
purchase the Cranberry Square Project or the Interests of the Entity owing the
Cranberry Square Project, the Cranberry Square Project shall be deleted from 
this Agreement, this Agreement shall be deemed to have been automatically
amended so as to delete the Project from this Agreement, and Buyer and Sellers 
shall proceed to close on the remaining Projects subject to a reduction in the
Consideration by the amount of the Consideration allocated to the Cranberry 
Square Project.

                   12.12.3.  Promptly after the Contract Date, Sellers shall
notify Green Spring Health Services, Inc. ("Green Spring") of this transaction 
and the sale of the Interests of the Entity owning the Woodlands I Project.
Buyer's obligation to purchase the Interests of the Entity owning the Woodlands
I Project is contingent upon (a) the exercise by Green Spring of the Green 
Spring Purchase Right or (b) the waiver by Green Spring on or before the Closing
Date (either inwriting or due to the passage of time) of its right, if any, to
purchase the Woodlands I Project pursuant to the terms contemplated by this
Agreement. If Green Spring exercises the Green Spring Purchase Right or does no 
waive such right (either in writing or due to the passage of time) on or before
the Closing Date, the Green Spring Purchase Right with respect to the Woodlands
I Project as it relates to the transaction contemplated by this Agreement, the
Woodlands I Project shall be deleted from this Agreement, this Agreement shall
be deemed to have been automatically amended so as to delete the Woodlands I
Project from this Agreement, and Buyer and Sellers shall proceed to

                                       36

<PAGE>


close on the remaining Projects, subject to a reduction in the Consideration by
the amount of the Consideration allocated to the Woodlands I Project.

All covenants made in this Agreement by Sellers shall survive the Closing for a
period of eighteen (18) months.

                13.    ENVIRONMENTAL WARRANTIES AND AGREEMENTS.

                  13.1.     Definitions.  Unless the context otherwise requires:

                           13.1.1. "Environmental Law" or "Environmental Laws"
shall mean all applicable past,present or future federal, state and local 
statutes, regulations, directives, ordinances, rules, court orders, decrees,
arbitration awards and the common law, which pertain to environmental matters,
contamination of any type whatsoever or health and safety matters, as such have 
been amended, modified or supplemented from time to time (including all present
and future amendments thereto and re-authorizations thereof). Environmental Laws
include, without limitation, those relating to: (i) the manufacture, processing,
use, distribution, treatment, storage, disposal, generation or transportation of
Hazardous Materials; (ii) air, soil, surface, subsurface, groundwater or noise 
pollution; (iii) Releases; (iv) protection of wildlife, endangered species,
wetlands or natural resources; (v) Tanks; (vi) health and safety of employees 
and other persons; and (vii) notification requirements relating to the 
foregoing. Without limiting the above, Environmental Law also includes the 
following: (i) the Comprehensive Environmental Response, Compensation and
Liability Act (42 U.S.C. ss.ss. 9601 et seq.), as amended ("CERCLA"); (ii) the
Solid Waste Disposal Act, as amended by the Resource Conservation and Recovery
Act (42 U.S.C. ss.ss. 6901 et seq.), as amended ("RCRA"); (iii) the Emergency
Planning and Community Right to Know Act of 1986 (42 U.S.C. ss.ss. 11001 et 
seq.), as amended; (iv) the Clean Air Act (42 U.S.C. ss.ss. 7401 et seq.), as
amended; (v) the Clean Water Act (33 U.S.C. ss.1251 et seq.), as amended; (vi)
the Toxic Substances Control Act (15 U.S.C. ss. 2601 et seq.), as amended; (vii)
the Hazardous Materials Transportation Act (49 U.S.C. ss.ss. 1801 et seq.), as 
amended; (viii) the Federal Insecticide, Fungicide and Rodenticide Act (7 U.S.C.
ss. 136 et seq.), as amended;(ix) the Federal Safe Drinking Water Act (42 U.S.C.
ss. 300f et seq.), as amended; (x) the Federal Radon and Indoor Air Quality
Research Act (42 U.S.C. ss. 7401 note, et seq.); (xi) the Occupational Safety 
and Health Act (29 U.S.C. ss. 651 et seq.), as amended; (xii) any state, county,
municipal or local statutes, laws or ordinances similar or analogous to 
(including counterparts of) any of the statutes listed above; and (xiii) any
rules, regulations, directives, orders or the like adopted pursuant to or
implementing any of the above.

                  13.1.2. "Environmental Permit" or "Environmental Permits"
shall mean licenses, certificates, permits, directives, requirements,
registrations, government approvals, agreements, authorizations, and consents
which are required under or are issued pursuant to an Environmental Law or are 
otherwise required by Governmental Authorities.

                                       37
<PAGE>


                  13.1.3. "Hazardous Conditions" refers to the existence or
presence of  any Hazardous Materials on, in, under, or at, the Projects
(including air, soil and groundwater) or any portion of any of them.

                  13.1.4. "Hazardous Material" or "Hazardous Materials" shall 
mean:

                          (a)  any chemical, pollutant, contaminant, pesticide,
petroleum or petroleum product or by product, radioactive substance, solid waste
(hazardous or extremely hazardous), special, dangerous or toxic waste,
substance, chemical or material regulated, listed, limited or prohibited under 
any Environmental Law, including without limitation: (i) friable or damaged
asbestos, asbestos-containing material, presumed asbestos-containing material,
polychlorinated biphenyls ("PCBs"), solvents and waste oil; (ii) any "hazardous
substance" as defined under CERCLA; and (iii) any "hazardous waste" as defined
under RCRA; and

                          (b)  even if not prohibited, listed, limited or
regulated by an Environmental Law, all pollutants, contaminants, hazardous,
dangerous or toxic chemical materials, wastes or any other substances, including
without limitation, any industrial process or pollution control waste (whether
or not hazardous within the meaning of RCRA) which could pose a hazard to the
environment, or the health and safety of any person or impair the use or value
of any portion of the Projects.

                 13.1.5. "Release" means any spill, discharge, leak, migration,
emission, escape, injection, dumping or other release or threatened release of
any Hazardous Material into the environment, whether or not notification or
reporting to any Governmental Authority was or is required. Release includes, 
without limitation, historical releases and the meaning of Release as defined
under CERCLA.

                 13.1.6. "Remedial Action" shall mean any and all corrective
or remedial action, preventative measures, response, removal, transport,
disposal, clean-up, abatement, treatment and monitoring of Hazardous Materials 
or Hazardous Conditions, whether voluntary or mandatory, and includes all
studies, assessments, reports or investigations performed in connection
therewith to determine if such actions are necessary or appropriate 
(including investigations performed to determine the progress or status of any
such actions), all occurring on or after the Contract Date.

                13.1.7. "Remedial Costs" shall include all costs, liabilities 
expenses and fees incurred on or after the date of this Agreement in connection 
with Remedial Action, including but not limited to: (i) the fees of 
environmental consultants and contractors; (ii) reasonable attorneys' fees
(including compensation for in-house and corporate counsel provided such 
compensation does not exceed customary rates for comparable services); (iii) the
costs associated with the preparation of reports, and laboratory analysis 
(including charges for expedited results if reasonably necessary); (iv) 
regulatory, permitting and review fees; (v) costs of soil and/or water treatment
(including groundwater monitoring)and/or

                                       38

<PAGE>



transport and disposal; and (vi) the cost of supplies, equipment, material and 
utilities used in connection with Remedial Action.

                  13.1.8.   "Tank" or "Tanks" means above-ground and underground
storage tanks, vessels and related equipment, including appurtenant pipes, lines
and fixtures containing or previously containing any Hazardous Material or
fraction thereof.

             13.2. Warranties.  Sellers, for themselves and for the 
Entities, hereby represent and warrant as follows with respect to each Project:

                   13.2.1.   Sellers and the Entities have made available or 
delivered to Buyer originals (or true, complete and accurate copies) of all of
the documents in their possession, custody or control, which documents include
and/or relate to:

                   (a) All approvals, plans, specifications, test borings,
percolation tests, engineering studies, surveys or other environmental data 
concerning the Projects;

                   (b) All permits (including Environmental Permits), approvals,
registrations, Tank registration and/or closure documentation, certificates,
applications, notices, orders, directives, legal pleadings, correspondence or
other documents of any nature that any Entity or Seller, any tenant of Entity,
any of Entity's predecessors-in-title or any tenant of Entity's
predecessors-in-title have submitted to, or received from, any Governmental
Authority regarding the Projects and their use, compliance or non-compliance
with Environmental Laws; and

                   (c) The results of any investigation of any of the 
Projects including, but not limited to, Phase I or Phase II site assessments,
asbestos inspection and/or removal reports, tests or investigations of soil or
other substrate air, groundwater, surface water, or the building interior, and 
any testing or investigation results relating to the removal or abandonment of 
any Tanks from the Projects.

                    13.2.2. To the knowledge of Sellers, each Project is owned
and operated in material compliance with all Environmental Laws and
Environmental Permits.

                    13.2.3. There are no pending or, to the Sellers' and
Entities' knowledge, threatened: (i) claims, complaints, notices, correspondence
or requests for information received by Sellers or the Entities with respect to
any violation or alleged violation of any Environmental Law or Environmental
Permit or with respect to any corrective or remedial action for or cleanup of
the Project or any portion thereof; and (ii) written correspondence, claims, 
complaints, notices, or requests for information from or to Sellers or Entities
regarding any actual, potential or alleged liability or obligation under or
violation of any Environmental Law or Environmental Permit with respect to the
Project or any portion thereof.

                                       39

<PAGE>

                    13.2.4. To Seller's knowledge, there have been no Release
and there has not been a threatened Release of a Hazardous Material on, in, 
under or at the Project or any portion thereof.

                    13.2.5.  No Project is listed, proposed or nominated for
listing on the National Priorities List pursuant to CERCLA (the "NPL"), the
Comprehensive Environmental Response and Liability Information System 
("CERCLIS") or on any other similar list of sites under analogous state laws.

                   13.2.6.  Except as listed and described on Exhibit "USTs",
there are no Tanks at, on or under the Project. Neither the Sellers nor the
Entities have removed, closed or abandoned any Tanks at the Projects, and
neither the Sellers nor the Entities have any knowledge of the existence, 
abandonment, closure or removal of Tanks at the Projects.

                   13.2.7.  To the knowledge of Sellers, there are no PCBs or
friable or damaged asbestos at the Projects.

                   13.2.8.   To the knowledge of Sellers, there has been no 
storage, treatment, disposal, generation, transportation or Release of any 
Hazardous Materials by any Entity or Seller or by any other person or entity for
which any Seller or Entity is or may be held responsible, at, on, under, or 
about any Project (or any portion thereof) in violation of Environmental Laws.

              13.3. Indemnity. Notwithstanding anything to the contrary in
this Agreement, with respect to each Project, each of the Sellers, and each of
Sellers' shareholders, partners and members, (collectively, jointly and
severally, "Post Closing Seller") agree to and do hereby indemnify, defend and
hold harmless Buyer, the REIT and each of their respective partners,
shareholders, agents, contractors, employees, officers, directors, trustees,
shareholders, and each of their successors and assigns (collectively, the "Buyer
Indemnified Parties"), from and against any and all liabilities, claims,
demands, suits, administrative proceedings, causes of action, costs, damages,
personal injuries and property damages, losses and expenses, both known and
unknown, present and future, at law or in equity (collectively, "Losses"),
arising out of, by virtue of or related in any way to a breach by Sellers of any
of their representations and warranties under Sections 13.2 through and
including 13.2.8.

         Without limiting any of Post-Closing Seller's above indemnification
obligations, Post-Closing Seller further acknowledges and agrees that its
obligation to indemnify the Buyer Indemnified Parties with respect to any breach
by Sellers of their representations and warranties under Sections 13.2 through
and including 13.2.8, includes, without limitation: (i) any and all Remedial
Costs associated with any Tank, Hazardous Material, Hazardous Condition or any
Release; (ii) to the maximum extent allowed by law, all fines and/or penalties
that may be imposed in connection with any Tank or the existence of any
Hazardous Material on, at, under, near, in or about the Projects; (iii) the
defense of any claim

                                       40

<PAGE>



made by any individual or entity (including any government, governmental agency
or entity) concerning any of the foregoing, which defense shall be conducted by 
counsel and with the assistance of environmental advisors and consultants,
in all cases subject to the prior written approval of Buyer; and (iv) reasonable
attorneys' fees and costs and environmental advisors' and consultants' fees 
incurred by any of the Buyer Indemnified Parties with respect to enforcing its
rights under this indemnification provision. This Section 13 shall survive the 
Closing for a period of thirty (30) months. Indemnification claims by Buyer
under this Section 13.3 are subject to Section 20.3.

         14.  ADDITIONAL CONDITIONS PRECEDENT TO CLOSING.

                14.1. Buyer's Conditions Precedent. In addition to the other
conditions enumerated in this Agreement, the following shall be additional
Buyer's Conditions Precedent:

                   14.1.1. Physical Condition.  The physical condition of each 
Project shall be substantially the same on the Closing Date as on the Contract
Date, reasonable wear and tear excepted, unless the alteration of said physical
condition is the result of Damage.

                  14.1.2.  Pending Actions.  At the Closing, there shall be no
administrative agency, litigation or governmental proceeding of any kind
whatsoever, pending or threatened, that, after the Closing, would, in Buyer's 
sole and absolute discretion, materially and adversely affect any Entity or the
value or marketability of any Project or the Projects as a whole, or the ability
of Buyer to operate any or all of the Projects in the manner it is (they are)
being operated on the Contract Date.

                 14.1.3. Zoning.  On the Closing Date, no proceedings shall be
pending or threatened that could or would involve the change, redesignation,
redefinition or other modification of the zoning classifications of (or any 
building, environmental, or code requirements applicable to) any or all of the 
Projects, or any portion thereof, or any property adjacent to any Project, in a
manner which, in Buyer's sole and absolute discretion, would materially and
adversely affect the value or marketability of any Project.

                 14.1.4. Flood Insurance.  As of the Closing Date, if any
Project is located in a flood plain, Buyer shall have obtained flood plain
 insurance in form and substance acceptable to Buyer.

                 14.1.5. Assumed Indebtedness. Sellers shall provide to Buyer
letters from each of the holders of the Assumed Indebtedness dated no earlier
than 30 days prior to the Closing Date, approving the transfer of the Interests 
to the Buyer, setting forth the amount of principal and interest outstanding as 
of the Closing Date, and stating that there has not been, and there does not
currently exist, any default under any of the Assumed Indebtedness. Such letters
shall be referred to collectively as the "Lenders' Approvals."

                                       41

<PAGE>

                 14.1.6. Satisfied Indebtedness.  Sellers shall provide to
Buyers payoff letters good through the Closing Date from all holders of the 
Satisfied Indebtedness stating
the amount required to pay off the Satisfied Indebtedness.

                 14.1.7. Owners. The composition of partners, shareholders and
members of each Entity and each Seller on the Closing Date shall be the same as
on the Contract Date, except for transfers to CPI Affiliates.

                 14.1.8. Bankruptcy.  As of the Closing Date, no Seller, no 
Entity and no Project is the subject of any bankruptcy proceeding for which
approval of this transaction has not been given and issued by the applicable
bankruptcy court.

                 14.1.9. Representations and Warranties True.  The 
representations and warranties of Sellers contained in this Agreement shall be
true and correct as of the Closing Date in all material respects, as though such
representations and warranties were made on such date.

                14.1.10. Covenants Performed.  All covenants and obligations of
Sellers required to be performed on or prior to the Closing Date shall have been
performed, in all material respects.

                14.1.11.  Approval by Buyer's Shareholders.  REIT's Board of 
Trustees and shareholders shall have approved this Agreement and the 
consummation of the transactions contemplated by this Agreement.

        14.2.   Seller's Additional Conditions Precedent. The following shall be
additional Seller's Conditions Precedent:

                14.2.1.   Representations and Warranties.  The representations
and warranties of Buyer contained in this Agreement shall be true and correct as
of the Closing Date, in all respects, as though such representations and
warranties were made on such date.

                14.2.2.   Covenants.  All covenants of Buyer required to be
performed on or prior to the Closing Date shall have been performed, in all
material respects.

         15.    LEASES-CONDITIONS PRECEDENT AND WARRANTIES WITH RESPECT THERETO.

                15.1. Warranties as to Leases. With respect to each of the
tenants listed on the Rent Roll (as defined in Exhibit "Seller's Deliveries")
provided to Buyer by Sellers and any other tenants leasing space in any or all
of the Projects as of the Closing Date (collectively, the "Tenants"), Sellers,
for themselves and for the Entities, represent and warrant to Buyer as of the
Contract Date and as of the Closing Date as follows:

                                       42

<PAGE>
                15.1.1. Each of the Leases is in full force and effect strictly
according to the terms set forth therein and in the Rent Roll, and has not been
modified, amended, or altered, in writing or otherwise. Each Tenant is legally 
required to pay all sums and perform all obligations set forth in the Leases,
without concessions, abatements, offsets or other bases for relief or
adjustment;

                15.1.2.  All obligations of the lessor under the Leases that 
accrue to the date of the Closing have been performed, including, but not
limited to, all required tenant improvements, cash or other inducements, rent
abatements or moratoria, installations and construction (for which payment in 
full has been made in all cases), and each Tenant has unconditionally accepted 
lessor's performance of such obligations. No Tenant has asserted any offsets,
defenses or claims available against rent payable by it or other performance or
obligations otherwise due from it under any Lease;

                15.1.3. Other than as shown on the Rent Roll, no Tenant is in 
default under or is in arrears in the payment of any sums or in the performance
of any obligations required of it under its Lease.  No Tenant has prepaid any 
rent or other charges;

                15.1.4. Each Entity and CPI as to Brandon have no reason to
believe that any Tenant is, or may become, unable or unwilling to perform any or
all of its obligations under its Lease, whether for financial or legal reasons
or otherwise;

               15.1.5.  Neither base rent ("Base Rent"), nor regularly payable 
estimated Tenant contributions or operating expenses, insurance premiums, real
estate taxes, common area charges, and similar or other "pass-through" or non-
base rent items including, without limitation, cost-of-living or so-called 
"C.P.I." or other such adjustments (collectively, "Additional Rent"), nor any
other item payable by any Tenant under any Lease has been heretofore prepaid for
more than one month nor shall it be prepaid between the Contract Date and the 
Closing Date for more than one month;

               15.1.6.  No guarantor(s) of any Lease has been released or
discharged, partially or fully, voluntarily or involuntarily, or by operation of
law, from any obligation under or in connection with any Lease or any
transaction related thereto;

               15.1.7.  Except as specifically disclosed on Exhibit
"Commissions," there are no brokers' commissions, finders' fees, or other
charges payable or to become payable to any third party on behalf of any Entity
as a result of or in connection with any Lease or any transaction related
thereto, including, but not limited to, any exercised or unexercised option(s)
to expand or renew;

               15.1.8. Each security deposit provided for under each Lease shall
be fully assigned to Buyer at the Closing.  No Tenant or any other party has
asserted any claim (other than for customary refund at the expiration of a 
Lease) to all or any part of any security deposit;

                                       43
<PAGE>


               15.1.9.  Sellers shall pay, and retain sole and exclusive\
responsibility for, all expenses due on or before the Closing Date connected
with or arising out of the negotiation, execution and delivery of the Leases,
including, without limitation, brokers' commissions (subject to Section 17.7), 
leasing fees and recording fees (as well as the cost of all tenant improvements,
subject to Section 17.7, not paid for by Tenants), and Sellers shall be deemed 
to have certified and warranted payment thereof to Buyer at the Closing;

              15.1.10.  Except as set forth on Exhibit "Tenant Purchase Rights",
no Tenant has, by virtue of its Lease or any other agreement or understanding,
any purchase option with respect to any Project, or any portion thereof, or any
right of first refusal to purchase any Project, or a portion thereof, whether
triggered by the transactions contemplated by this Agreement or by a subsequent
sale of such Project or a portion thereof. Except as set forth on the Rent Roll,
no Tenant has, by virtue of its Lease, or any other agreement or understanding 
any of the following: (a) the right or option to expand its tenancy into space
at any Project other than the space that such Tenant is currently occupying; 
(b) the right or option to terminate its Lease; and (c) the right or option to 
contract the space at any Project that such Tenant is currently occupying;

             15.1.11.  (a) Except as specifically disclosed on the Rent Roll 
delivered to Buyer, no Tenant has sublet its leased premises; and (b) there are 
no outstanding requests from any Tenants to Seller, requesting any consent to an
assignment of the Tenant's Lease or to a sublease of all or some portion of a
Tenant's leased premises.

         Each Seller hereby indemnifies, defends and holds Buyer harmless from
and against all loss, damage, liability, cost, expense (including, but not
limited to, reasonable fees of attorneys of Buyer's choice) and charges which
Buyer may incur, or to which Buyer may become subject, as a consequence of any
breach of the warranties contained in this Section 15. The foregoing indemnity
shall survive the Closing for a period of eighteen (18) months.

                  15.2. Estoppel Certificates from Tenants. Sellers shall use
Sellers' commercially reasonable efforts to obtain, on or prior to the Closing
Date, a tenant's estoppel certificate from Tenants occupying at least eighty
percent (80%) of each Project (except Tred Avon) or such larger percentage as
Buyer's lender or lenders may require (provided, that Buyer advises Sellers of
lender requirements at least thirty (30) days before Closing) (the "Estoppel
Certificate"), dated no earlier than thirty (30) days prior to the Closing Date,
from each of the Tenants. The Estoppel Certificate shall be certified to Buyer,
the Entity owning the Project in which the applicable Tenant is located, and any
other party designated by Buyer. If Sellers (despite Sellers' required best
efforts) are unable to obtain an Estoppel Certificate from the required
percentage of Tenants Buyer's sole remedy shall be to proceed to close and
accept Seller's own Estoppel Certificate with respect to the Lease and tenancy
for which Sellers fail to procure an Estoppel Certificate from the relevant
Tenant (and any Estoppel Certificate so executed by a Seller shall also be
tailored, in a manner mutually and reasonably acceptable to Buyer and such
Seller, to reflect its issuance by the landlord, rather than the

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<PAGE>


Tenant in question). Each such Estoppel Certificate shall be substantially in 
the form attached hereto as Exhibit "Tenant Estoppel Certificate" or in such 
other form as Buyer's lender or lenders may require. At Buyer's request, when 
Sellers request the Tenant Estoppels, Sellers shall simultaneously request, and
thereafter Sellers shall use Sellers' commercially reasonable efforts to obtain,
on or before the Closing Date, from each Tenant a subordination, non-disturbance
and attornment agreement in such form and content as Buyer or Buyer's lender may
require.

         16.       CLOSING DELIVERIES.

                  16.1. Sellers' Deliveries. At the Closing (or such other times
as may be specified below), Sellers shall deliver or cause to be delivered to
Buyer the following, in form and substance reasonably acceptable to Buyer and
Sellers:

                   16.1.1.   Assignment of Interests.  As to each Entity, an 
Assignment and Assumption Agreement, an Amendment to the Entity Agreement, and 
an Amendment to the filed Entity Certificate setting forth the assignment by
each of the Sellers of such Seller's Interests and his, her or its withdrawal
from the Entity and the admission of the Buyer and/or its designee(s) as
partners of the Entity, which amendment shall be executed and acknowledged by
all Sellers and the Buyer.

                  16.1.2.   Release.  A release from each Seller releasing each
Entity and the Buyer (and its designee(s)) as partners of the Entities from any
obligations and liabilities with respect to the original formation of the 
Entities, and any other matter arising from business done, transactions entered
into or events occurring prior to the Closing Date.

                 16.1.3.   Opinion.  The opinion, in form and substance
reasonably acceptable to Buyer and Buyer's counsel, of Dan R. Skowronski,
Esquire, General Counsel of Constellation Holdings, Inc., to the effect that,
providing, or with respect to:

                           (a)  Each Entity is a duly organized and validly
existing entity in good standing under the laws of the State of Maryland;

                           (b)  (i) the legal existence and good standing of
each Entity and each Seller in Maryland; (ii) the due authorization, execution 
and delivery of this Agreement, and the other documents required (under the
terms of this Agreement) to be delivered by each Seller; (iii) that this
Agreement and the other documents required (under the terms of this Agreement)
to be delivered by each Seller, constitute the legal, valid and binding 
obligations of such Seller, enforceable against it in accordance with their
respective terms, except to the extent that enforceability may be limited by
bankruptcy, insolvency, reorganization, moratorium, fraudulent transfer and
other similar laws of general applicability relating to or affecting the 
enforcement of creditors' rights and by the effect of general principles of
equity (regardless of whether enforceability is considered in a proceeding of 
equity or at law;

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<PAGE>


               (c)  The execution and delivery of this Agreement and all other
agreements delivered in connection herewith or at the Closing, the consummation
of the transactions herein contemplated, and compliance with the terms of this
Agreement and all other agreements delivered in connection herewith or at the
Closing will not conflict with, or result in a breach of, any of the terms,
conditions or provisions of, or constitute a default under, any note, indenture,
mortgage, deed of trust, contract or other agreement or instrument to which any
Entity is a party or by which any Entity is bound, or any law or order, rule,
regulation, writ, injunction or decree of any government, governmental
instrumentality or court, domestic or foreign; and

              (d)  There is no litigation or investigation pending or, to the
best of such counsel's knowledge, threatened against any Entity, any Project, 
or any part thereof.

               16.1.4.   Lenders' Approvals and Payoff Letters.  The Lenders'
Approvals from all holders of the Assumed Indebtedness in conformity with 
Section 14.1.5 and the payoff letters required by Section 14.1.6.

              16.1.5.   Estoppel Certificates.  The Estoppel Certificates of all
Tenants in conformity with Section 15.2;

              16.1.6.   Keys.  Keys to all locks located at each Project;

              16.1.7.   Affidavit of Title and ALTA Statement.  As to each 
Project, an Affidavit of Title (or comparable document) as reasonably required
by the Title Company in the Commonwealth of Pennsylvania as a condition to the
deletion of the general exceptions of Schedule B, Section 2 of each Title
Policy, executed by the applicable Entity or Seller, as applicable, and in form
and substance acceptable to the Title Company and to Buyer;

              16.1.8.   Letters to Tenants.  If requested by Buyer, letters 
executed by the applicable Entities and, if applicable, its management agent,
addressed to all Tenants, in form provided by Buyer, notifying all Tenants of
the transfer of control of the Projects and directing payment of all rents
accruing after the Closing Date to be made to Buyer or at its direction;

              16.1.9.   Title Policies.  The title policies (or "marked-up" 
Title Reports) issued by the Title Company, dated as of the Closing Date in the
amount of the Consideration allocated to each Project, in accordance with the 
requirements of Section 9 (it being understood that CPI as to Brandon will
provide any certificates or undertakings required in order to induce the Title
Company to insure over any "gap" period resulting from any delay in recording of
documents or later-dating the title insurance file);

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<PAGE>


             16.1.10.  Original Documents.  To the extent not previously 
delivered to Buyer, originals of the Leases, Assigned Contracts and Governmental
Approvals;

             16.1.11.  Closing Statement.  A closing statement conforming to the
proration and other relevant provisions of this Agreement (the "Closing
Statement") duly executed by Sellers;

             16.1.12.  Plans and Specifications.  All plans and specifications 
relating to the Projects in any Entity's or Seller's possession and control or
otherwise available to any Entity or Seller;

             16.1.13.  Tax Bills.  Copies of the most currently available Tax
Bills to the extent not previously delivered to Buyer;

             16.1.14.  Entity Transfer Certificate.  Entity transfer
certifications confirming that each Seller is a "United States Person"
within the meaning of Section 1445 of the Internal Revenue Code of 1986, as
amended;

             16.1.15.  Rent Roll.  A Rent Roll, prepared as of the Closing Date,
certified by the applicable Sellers to be true, complete and correct through the
Closing Date;

             16.1.16.  Registration Rights Agreement.  The Registration Rights 
Agreement, dated as of the Closing Date and duly executed by the Sellers;

             16.1.17.  Share Schedule.  The Share Schedule, duly executed by
Sellers;

             16.1.18.  Certificates of Occupancy.  Currently valid certificates 
of occupancy (or comparable permits or licenses), to the extent in Sellers'
possession or control, with respect to the entirety of each Project;

             16.1.19.  Closing Certificate.  A certificate, signed by Sellers, 
certifying to the Buyer that the representations and warranties of Sellers 
contained in this Agreement are true and correct on all material respects as of
the Closing Date and that all covenants required to be performed by Sellers
prior to the Closing Date have been performed in all material respects;

             16.1.20.  Resolutions, Consents, Approvals.  Certified Resolutions,
consents, and approvals of each Sellers evidencing such Seller's authority to
execute this Agreement and consummate the transactions contemplated by this
Agreement.

             16.1.21.  Good Standing Certificate.  Currently dated good standing
certificates for the Sellers and the Entities.

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<PAGE>


             16.1.22.  Deed.  Special Warranty Deed, Executed by CPI, in
recordable form conveying Brandon to Buyer free and clear of all liens, claims 
and encumbrances except for the Permitted Exceptions.

             16.1.23.  Bill of Sale.  General Warranty Assignment and Bill of
Sale, executed by CPI, assigning, conveying and warranting to Buyer title to the
Personal Property and Inventory as to Brandon, free and clear of all
encumbrances, other than the Permitted Exceptions.

             16.1.24.  General Assignment.  An assignment, executed by CPI to
Buyer, of all right, title and interest of Contributor and its agents in and to
the Intangible Personal Property as to Brandon.

             16.1.25.  Assignment of Contracts.  An assignment, executed by CPI 
and Buyer, to Buyer of CPI's right, title and interest in and to those of the 
Contracts that will remain in effect after Closing. CPI shall also assign to
Buyer all guarantees and warranties given to CPI in connection with the 
operation, construction, improvement, alteration or repair of any or all of 
Brandon.

             16.1.26.  Assignment of Leases and Estoppel Certificates.  An 
assignment of CPI's right, title and interest in and to the Leases as to Brandon
(including all security deposits and/or other deposits thereunder), with 
customary reciprocal indemnity provisions.

             16.1.27.  Option/ROFR.  The signed Option/ROFR Agreements.

             16.1.28.  Constellation Lease.  The signed Constellation Lease.

             16.1.29.  Development Management Agreement.  The signed Development
Management Agreement.

             16.1.30. TIF Agreement. The signed TIF Agreement.

             16.1.31.  License Agreements.  Signed License Agreements in form a
nd content reasonably acceptable to Sellers and Buyer giving Buye r, and Buyer's
successors and assigns, the right to use the names "National Business Park".
"Constellation Centre", and "Piney Orchard" in connection with the ownership and
operation of those Projects.

            16.1.32.  Articles of Transfer.  Signed articles of transfer to the
extent required by the State Department of A ssessments and Taxation of
Maryland.

            16.1.33.  Other.  Such other documents and instruments as may
reasonably be required by Buyer (including, without limitation, those of the
Seller's Deliveries in Seller's possession or control that have not previously 
been delivered to Buyer), its (or its 

                                       48

<PAGE>

underwriters' or lenders') counsel or the Title Company and that may be 
necessary to consummate the transactions that are the subject of this Agreement
and to otherwise give effect to the agreements of the parties hereto.

         16.2. Buyer's. As a condition precedent to Seller's obligationclose 
("Seller's Condition Precedent"), Buyer shall cause to be delivered to
Sellers the following, each in form and substance reasonably acceptable to
Sellers and Buyer and their respective counsel:

             16.2.1.   The Consideration.  The Consideration required to be
delivered by Buyer to Sellers under this Agreement.

             16.2.2.   Organizational Documents.  (i) A copy certified by the 
Secretary of State of the State of Maryland of the Declaration of Trust of the
REIT and a good standing certificate for the REIT; (ii) a copy certified by the
Secretary of State of the State of Delaware of the certificate of limite
partnership of the Buyer and a good standing certificate for the Buyer; and 
(iii) a copy, certified by the secretary or an assistant secretary of the REIT,
of the resolution of the REIT's board of directors, authorizing the transactions
described herein;

             16.2.3.   Closing Statement.  A Closing Statement, duly executed 
by the Buyer;

             16.2.4.   Registration Rights Agreement.  The Registration Rights
Agreement, duly executed by the REIT;

             16.2.5.   Share  Schedule.  Share Schedule, duly executed by the 
Buyer;

             16.2.6.   Tenant Letters.  If Buyer has requested such letters, the
Tenant Letters, duly executed by the Buyer;

             16.2.7.   Opinion.  An opinion of counsel for COPLP and the REIT, 
in form and substance reasonably satisfactory to Seller and Seller's counsel,
providing or with
respect to: (i) the legal existence and good standing of COPLP and the REIT;
(ii) the due authorization, execution and delivery of this Agreement, and the
other documents required (under the terms of this Agreement) to be delivered by
COPLP and the REIT, as applicable; (iii) that the Shares issued and delivered to
Sellers as part of the Consideration have been duly authorized and validly
issued by the REIT and constitute fully paid, non-assessable shares of the REIT,
free from all pre-emptive rights; (iv) that this Agreement and the other
documents required (under the terms of this Agreement) to be delivered by each
of COPLP and the REIT, as applicable, constitute the legal, valid and binding
obligations of COPLP and the REIT, enforceable against them in accordance with
their respective terms, except to the extent that enforceability may be limited
by bankruptcy, insolvency, reorganization, moratorium, fraudulent transfer and
other similar laws of general applicability relating to or affecting the

                                       49

<PAGE>


enforcement of creditors' rights and by the effect of general principles of
equity (regardless of whether enforceability is considered in a proceeding of
equity or at law;

              16.2.8.   ROFR.  The signed ROFR Agreements.

              16.2.9.   Constellation Lease.  The signed Constellation Lease;

              16.2.10.  Development Management Agreement.  The signed
Development Management Agreement;

              16.2.11. TIF Agreement. The signed TIF Agreement.

              16.2.12.  Licenses.  The licenses referred to in Section 16.1.31.

              16.2.13.  Articles of Transfer.  The articles of transfer 
referred to in Section 16.1.32.

              16.2.14.  Other.  Such other documents and instruments as may
reasonably be required by Sellers or its or their respective counsel or the 
Title Company and that are necessary to consummate the transaction which is the
subject of this Agreement and to otherwise effect the agreements of the parties 
hereto.

         17.     PRORATIONS AND ADJUSTMENTS.

         The following shall be prorated and adjusted between Sellers and Buyer
as of the Closing Date, except as otherwise specified:

                  17.1. The amount of all security and other Tenant deposits,
and interest due thereon, if any, shall be credited to Buyer;

                  17.2. Buyer and Sellers shall divide the cost, if any, of any
closing escrows hereunder equally between them;

                  17.3. Water, electricity, sewer, gas, telephone and other
utility charges based, to the extent practicable, on final meter readings and
final invoices, or, in the event final readings and invoices are not available,
based on the most currently available billing information, and reprorated upon
issuance of final utility bills;

                  17.4. Amounts paid or payable under any Assigned Contracts
shall be prorated based, to the extent practicable, on final invoices, or, in
the event final invoices are not available, based on the most currently
available billing information, and reprorated upon issuance of final invoices;

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<PAGE>


                  17.5. All real estate, personal property and ad valorem taxes
applicable to the Projects and levied with respect to current tax year shall be
prorated as of the Closing Date, utilizing the actual final Tax Bills for those
Projects. Prior to or at the Closing, Sellers shall pay or have paid all Tax
Bills that are due and payable prior to or on the Closing Date and shall furnish
evidence of such payment to Buyer and the Title Company. Each party's respective
obligations to reprorate real estate taxes shall survive the Closing.

                  17.6. All assessments, general or special, shall be prorated
as of the Closing Date on a "due date" basis such that the applicable Entity or
Seller shall be responsible for any installments of assessments which are first
due or payable prior to the Closing Date and Buyer shall be responsible for any
installments of assessments which are first due or payable on or after the
Closing Date;

                  17.7. Commissions of leasing and rental agents for any Lease
entered into as of or prior to the Contract Date, whether with respect to base
lease term or future expansions, shall be paid in full at or prior to the
Closing by Seller, without contribution or proration from Buyer, except for
renewal commissions as disclosed to Buyer in Exhibit "Commissions". As to Leases
entered into between the Contract Date and the Closing Date in accordance with
Section 12.1, commissions shall be prorated as of the Closing Date based upon
the portion of the term of the Lease before Closing and the portion of the term
of this Lease after Closing. At Closing, COPT shall reimburse CPI the amount of
leasing commissions payable to unaffiliated third-parties and tenant
improvements costs payable to unaffiliated third-parties incurred by CPI with
respect to Leases entered into, subject to Section 12.1 of this Agreement, after
March 9, 1998 at the Project known as "One Constellation Centre", the amount
claimed for reimbursement evidenced by invoices or paid receipts from such third
parties or other evidence of expense reasonably required by Buyer..

                  17.8. Current interest under Assumed Indebtedness shall be
prorated as of the Closing Date.

                  17.9. All Base Rents and other charges, including, without
limitation, all Additional Rent, shall be prorated as of the Closing Date. At
the time(s) of final calculation and collection from Tenants of Additional Rent
for 1998, there shall be a re-proration between Sellers and Buyer as to
Additional Rent adjustments, with such re-prorations being payable to the
appropriate recipient in cash. Such re-proration shall be paid upon Buyer's
presentation of its final accounting to Seller, certified as to accuracy by
Buyer. At the Closing, no "Delinquent Rents" (rents or other charges that are
due as of the Closing) shall be prorated in favor of Seller. The parties'
respective obligations to reprorate Additional Rent shall survive the Closing.
Notwithstanding the foregoing, Buyer shall use reasonable efforts after the
Closing Date to collect any Delinquent Rents due to Sellers from Tenants, but
Buyer shall not be required to sue any Tenants. All rents and other charges
received by (or for the benefit of) Buyer from any Tenant after the Closing
shall be first applied against current and past due obligations owed to, or for
the benefit of, Buyer (with respect to those obligations accruing subsequent to
the Closing Date), and any excess shall be delivered to Seller, but only to the

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<PAGE>


extent of amounts in default and owed to, and for the benefit of, Sellers for
the period prior to the Closing Date. In no event, however, shall any sums be
paid to Sellers to the extent Sellers have been previously reimbursed for such
default out of any security deposit and security deposits have been
appropriately prorated hereunder; and

                  17.10. Such other items that are customarily prorated in
transactions of this nature shall be ratably prorated.

                  17.11. With respect to the Project known as "Cranberry
Square", at Closing, Buyer shall reimburse CPI amounts expended by CPI from and
after March 9, 1998 until the Closing Date on the expansion of the Cranberry
Square Project, subject, however, to the limitation, that the amount payable to
CPI under this Section 17.11 shall not exceed the amount determined by
subtracting the costs to complete the expansion of the Cranberry Square Project
after the Closing Date as reasonably determined by Buyer and Sellers from Two
Million Two Hundred Thousand Dollars ($2,200,000.00). Amounts claimed for
reimbursement shall be evidenced by invoices or paid receipts from third-parties
not affiliated with CPI, or other evidence of expense reasonably required by
Buyer.

         For purposes of calculating prorations, Buyer shall be deemed, through
control of the Entities, to be in title to the Projects, and therefore entitled
to the income therefrom and responsible for the expenses thereof, for the entire
Closing Date. All such prorations shall be made on the basis of the actual
number of days of the year and month that shall have elapsed as of the Closing
Date. Bills received after the Closing that relate to expenses incurred,
services performed or other amounts allocable to the period prior to the Closing
Date shall be paid, in cash, by Seller, to the extent due and owing. Bills
received by Sellers after the Closing Date that relate to expenses incurred,
services performed or other amounts allocable to the period on or after the
Closing Date, shall be paid, in cash, by the Buyer, to the extent due and owing.

         18.       CLOSING EXPENSES.

                  18.1. Sellers will pay the entire cost of all assumption
charges, release fees, prepayment fees and any other fees or costs in connection
with the assumption, payoff, release and satisfaction of the Assumed Mortgages
and the Satisfied Mortgages, and all fees imposed by its accountants and
attorneys and consultants in connection with this Agreement and the transaction
contemplated hereunder. Buyer will pay the entire cost of the title policies,
the Surveys (inclusive of any updates thereof), and all fees imposed by its
accountants, attorneys, and environmental and engineering consultants.

                  18.2. Although Seller and Buyer believe that no real estate
transfer or recording fees or taxes will be due in connection with the
assignment of the Interests, if it is finally determined that such taxes are due
and payable in connection herewith, then the Buyer and the Sellers which held
Interests the transfer of which is deemed subject to real estate transfer tax
shall divide equally the costs of contesting such taxes and shall divide equally
the 

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<PAGE>


full amount of such taxes if they are finally determined to be payable. This
Section 18.2 shall survive Closing.

                  18.3. Sellers and Buyer shall divide equally all recordation
taxes and fees, and all realty transfer taxes applicable to the conveyance of
Brandon.

         19.       DESTRUCTION, LOSS OR DIMINUTION OF PROJECTS.

         If, prior to the Closing, all or any portion of any Project is damaged
by fire or other natural casualty (collectively, "Damage"), or is taken or made
subject to condemnation, eminent domain or other governmental acquisition
proceedings (collectively, "Eminent Domain"), then the following procedures
shall apply:

                  19.1. If the aggregate cost of repair or replacement in
connection with any Damage at any Project or the value of the Eminent Domain
involving any single Project (collectively, "repair and/or replacement") is
$200,000.00 or less (on a per Project basis), in the mutual and reasonable
opinions of Buyer and Seller, Buyer shall close and take the Project(s) in
question as diminished by the Damage or Eminent Domain, as the case may be,
subject to a reduction in the Contribution Consideration otherwise due at the
Closing, in the full amount of the cost of repair and/or replacement. Any
casualty insurance or condemnation proceeds shall be the sole property of
Seller.

                  19.2. If the aggregate cost of repair and/or replacement at
any single Project is greater than $200,000.00, in the mutual and reasonable
opinions of Buyer and Seller, then Buyer, in its sole and absolute discretion,
may elect any of the following options: (i) Buyer may delete and eliminate from
this Agreement any Project that is in need of repair and/or replacement in
excess of $200,000.00 by giving written notice to Seller, in which event (A)
this Agreement shall be deemed to have been automatically amended so as to
eliminate the deleted Projects herefrom, and (B) Buyer and Sellers shall proceed
to close on the remaining Projects (i.e., the non-deleted Projects) subject to
an appropriate and commensurate reduction in the Consideration (which reduction
shall include, without limitation, an amount equal to the full cost of repair
and/or replacement of any portion of any non-deleted Project that Buyer proceeds
to purchase); or (iii) Buyer may proceed to close on all of the Projects,
subject to (1) a reduction in the Consideration equal to $200,000.00, on a per
Project basis, otherwise due at the Closing and (2) an assignment of the
proceeds of Seller's casualty insurance proceeds for all Damage (or condemnation
awards for any Eminent Domain) in excess of $200,000.00, on a per Project basis,
together with payment to Buyer by Sellers of any uninsured or deductible amount
not covered by such proceeds. In such event, Sellers shall fully cooperate with
Buyer in the adjustment and settlement of the insurance claim or governmental
acquisition proceeding and if, as of the Closing, the insurance proceeds (or
condemnation award) assignable to Buyer shall not have been collected from the
insurer or Governmental Authority, then a cash credit in the amount thereof
shall be given to Buyer, to be repaid to Sellers out of and upon Buyer's actual
receipt of insurance proceeds. The proceeds and benefits under any rent loss or
business interruption policies attributable to the

                                       53

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period following the Closingshall likewise be transferred and paid over (and, if
applicable, likewise credited on an interim basis) to Buyer.

                  19.3. In the event of a dispute between Sellers and Buyer with
respect to the cost of repair and/or replacement with respect to the matters set
forth in this Section 19, an engineer designated by Sellers and an engineer
designated by Buyer shall select an independent engineer licensed to practice in
the jurisdiction where the Project in question is located who shall resolve such
dispute. All fees, costs and expenses of such third engineer so selected shall
be shared equally by Buyer and Seller.

         20.       DEFAULT.

                  20.1. Default by Seller. If any of Sellers' representations
and warranties contained herein shall not be true and correct on the Contract
Date and continuing thereafter through and including the Closing Date, or if any
Seller fails to perform any of the covenants and agreements contained herein to
be performed by such Seller within the time for performance as specified herein
(including Seller's obligation to close), or if any of the Buyer's Conditions
Precedent shall not have been satisfied, Buyer may elect either to (i) terminate
Buyer's obligations under this Agreement by written notice to Sellers, in which
event Buyer shall retain all rights and remedies available to it; or (ii) close,
in which event Buyer may file an action for either or both of specific
performance and damages to compel Sellers to cure all or any of such default(s),
in whole or in part, whereupon Buyer shall be entitled to deduct from the
Consideration, the cost of such action and cure, and all reasonable expenses
incurred by Buyer in connection therewith, including, but not limited to,
attorneys' fees of Buyer's counsel. Notwithstanding anything to the contrary
herein and in addition to any other remedies of Buyer, Buyer shall be entitled
to recover actual (but not consequential) damages suffered by Buyer by reason of
Seller's defaults hereunder and/or any delay occasioned thereby, including,
without limitation, Buyer's Reasonable Costs. The remedies of Buyer set forth in
this Section 20.1 shall be in addition to remedies otherwise applicable or
provided in this Agreement or otherwise available to Buyer at law or in equity,
including, without limitation, specific performance, it being understood that
Buyer's rights and remedies under this Agreement shall always be non-exclusive
and cumulative and that the exercise of one remedy or form of relief available
to Buyer hereunder shall not be exclusive or constitute a waiver of any other.
Buyer's remedies under this Section 20.1 shall not be limited by Section 20.3.

                  20.2. Default by Buyer. In the event Buyer defaults in its
obligations to acquire the Interests and Brandon, then Sellers' sole and
exclusive remedy shall be to cause the Escrowee to deliver the Proceeds,
together with all interest earned thereon, to Seller, the amount thereof being
fixed and liquidated damages, it being understood that Sellers' actual damages
in the event of such default are difficult to ascertain and that such proceeds
represent the parties' best current estimate of such damages. Sellers shall have
no other remedy for any default by Buyer prior to Closing.

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                  20.3.       Indemnification of Buyer.

                      20.3.1.   Indemnification.  Each of Seller and each of
Seller's shareholders, members and partners, jointly and severally, as the case
may be, shall and does hereby indemnify, protect, defend and hold the Buyer
Indemnified Parties harmless from and against any claims, losses, demands,
liabilities, suits, costs and damages suffered by the Buyer Indemnified Parties,
including consequential as well as actual damages and attorneys' fees of counsel
selected by the Buyer Indemnified Parties and other costs of defense, incurred,
arising against, or suffered by, the Buyer Indemnified Parties or its assigns as
a direct or indirect consequence of (i) any breach of any representation,
warranty or covenant made in this Agreement by Seller, or any other default by 
Seller, whether discovered before or after the Closing or (ii) any default 
claim, action or omission arising or alleging to arise under the Existing Loan
Documents and relating to the period prior to the Closing, whether asserted 
before or after the Closing. This indemnification obligation shall expire 
eighteen (18) months from the Closing Date, except as to until thirty (30) 
months after the date of this Agreement, and except as to claims under Section 
11.1 which may be made until the expiration of the time period under the statute
of limitation applicable to such claims..

                  20.3.2.   Limitation of Claims.  No claims for
indemnification under this Agreement may be asserted by Buyer Indemnified
Parties against the Sellers until the aggregate amount of such indemnification 
claims exceeds $125,000.00, whereupon all such amounts may be claimed.

                  20.4.     Indemnification of Sellers.

                       20.4.1. Indemnification.  Buyer shall indemnify, protect,
defend and hold Sellers' and each of Sellers' shareholders, members and partners
(the "Seller Indemnified Parties") harmless from and against any claims, losses,
demands, liabilities, suits, costs and damages suffered by the Seller
Indemnified Parties, including consequential as well as actual damages an
attorneys' fees of counsel selected by the Seller Indemnified Parties and other
costs of defense, incurred, arising against, or suffered by, the Seller 
Indemnified Parties or its assigns as a direct or indirect consequence of any
breach of any representation, warranty or covenant made in this Agreement by
Buyer, or any other default by Buyer, whether discovered before or after the
Closing. This indemnification obligation shall survive Closing.

                  20.5. Buyer Notice and Right to Cure. Anything contained in
this Agreement to the contrary notwithstanding, any thing or act which would
otherwise be a default hereunder by Buyer shall not be a default unless Sellers
shall have given Buyer notice of such default, and Buyer shall have failed to
cure the same within thirty (30) days after such notice. No notice of default
shall be required in the case of Buyer's default in failing to complete Closing
on the required Closing Date.

                                       55

<PAGE>


                  20.6. Sellers' Notice and Right to Cure. Anything contained in
this Agreement to the contrary notwithstanding, any thing or act which would
otherwise be a default hereunder by Sellers shall not be a default unless Buyer
shall have given Sellers notice of such default, and Sellers shall have failed
to cure the same within thirty (30) days after such notice. No notice of default
shall be required in the case of Sellers' default in failing to complete Closing
on the required Closing Date.

         21.       SUCCESSORS AND ASSIGNS.

         The terms, conditions and covenants of this Agreement shall be binding
upon and shall inure to the benefit of the parties and their respective
nominees, successors, beneficiaries and assigns; provided, however, no direct or
indirect conveyance, assignment or transfer of any interest whatsoever of, in or
to any or all of the Projects or of this Agreement shall be made by Sellers
during the term of this Agreement except to CPI Affiliates, as permitted in
Section 11.1.4. Buyer may assign all or any of its right, title and interest
under this Agreement to the Buyer, the REIT or to any corporate or partnership
entity affiliated with, or related to, the Buyer or the REIT ("Affiliate"). For
purposes of this Agreement, an Affiliate shall, without limitation, include any
entity having common ownership or management with Buyer or the REIT. No such
assignee shall accrue any obligations or liabilities hereunder until the
effective date of such assignment. In addition to its right of assignment, Buyer
shall also have the right, exercisable at or prior to the Closing, to designate
any Affiliate, as the contract party under any contract to be entered into at
Closing pursuant to the terms of this Agreement by Buyer, or as the grantee or
transferee of any or all of the conveyances, transfers and assignments to be
made by Sellers at the Closing hereunder, independent of, or in addition to, any
assignment of this Agreement. In the event of an assignment of this Agreement by
Buyer (but not in the event of the designation of any Affiliate), its assignee
shall be deemed to be the Buyer hereunder for all purposes hereof, and shall
have all rights of Buyer hereunder (including, but not limited to, the right of
further assignment). In the event that an Affiliate shall be designated as a
transferee hereunder, that transferee shall have the benefit of all of the
representations and rights which, by the terms of this Agreement, are
incorporated in or relate to the conveyance in question.


                                       56

<PAGE>

         22.       LITIGATION.

         Sellers and Buyer waive all rights to a jury trial with respect to any
disputes relating to this Agreement, whether arising before or after Closing. In
the event of litigation between the parties with respect to any Project, this
Agreement, the performance of their respective obligations hereunder or the
effect of a termination under this Agreement, the losing party shall pay all
costs and expenses incurred by the prevailing party in connection with such
litigation, including, but not limited to, reasonable attorneys' fees of counsel
selected by the prevailing party. The parties hereby further acknowledge and
agree that in the event of litigation between them, as contemplated above, and
the resolution of that litigation through compromise, settlement, or partial
judgment, the court before which such litigation is initially brought shall have
the right to allocate responsibility, between Sellers and Buyer, for all costs
and expenses (including, but not limited to, attorneys' reasonable fees)
incurred by both Sellers and Buyer in the pursuit of that litigation resolved
through compromise, settlement or partial judgment. Notwithstanding any
provision of this Agreement to the contrary, the obligations of the parties
under this Section 22 shall survive termination of this Agreement and the
Closing, if applicable.

         23.       NOTICES.

         Any notice, demand or request which may be permitted, required or
desired to be given in connection therewith shall be given in writing and
directed to Sellers and Buyer as follows:

                                    Sellers:

                                    Constellation Real Estate, Inc.
                                    8815 Centre Park Drive - Suite 400
                                    Columbia, MD  21045
                                    Attention: General Counsel

                                       and

                                    Constellation Holdings, Inc.
                                    250 West Pratt Street
                                    Baltimore, MD   21201-2423
                                    Attention: Dan R. Skowronski, Esquire

                                       57

<PAGE>


                          With a copy to its attorneys:

                                    Stephen L. Owen, Esquire
                                    Piper & Marbury LLP
                                    36 South Charles Street
                                    Baltimore, MD   21201-3018

                                            Buyer:

                                    Corporate Office Properties Trust
                                    One Logan Square, Suite 1105
                                    Philadelphia, PA   19103
                                    Attention: Clay W. Hamlin, III
                                               President and Chief Executive
                                               Officer

                          With a copy to its attorneys:

                                    F. Michael Wysocki, Esquire
                                    Saul, Ewing, Remick & Saul LLP
                                    Centre Square West
                                    1500 Market Street - 38th Floor
                                    Philadelphia, PA   19102

Notices shall be deemed properly delivered and received when and if either (i)
personally delivered, including via facsimile; or (ii) on the first business day
after deposit with a commercial overnight courier for delivery on the next
business day. Any party may change its address for delivery of notices by
properly notifying the others pursuant to this Section 23.

         24.       BENEFIT.

         This Agreement is for the benefit only of the parties hereto and their
nominees, successors, beneficiaries and assignees as permitted in Section 21
above and no other person or entity shall be entitled to rely hereon, receive
any benefit herefrom or enforce against any party hereto any provision hereof.

         25.       LIMITATION OF LIABILITY.

                  25.1. Upon the Closing, neither the REIT nor the Buyer shall
assume or undertake to pay, satisfy or discharge any liabilities, obligations or
commitments of Sellers other than those specifically agreed to between the
parties and set forth in this Agreement. Except as otherwise specifically
provided in this Agreement, neither the REIT nor the Buyer shall assume or
discharge any debts, obligations, liabilities or commitments of Seller, whether
accrued now or hereafter, fixed or contingent, known or unknown. Neither the
holders of Shares nor the trustees, officers, employees or agents of the REIT
shall be liable under this

                                       58

<PAGE>

Agreement and all parties hereto shall look solely to the REIT assets for the
payment of any claim or for the performance of any obligation of the REIT as a 
party to this Agreement, both in its own capacity and in its capacity as a
general partner of the Buyer.

                  25.2. None of the shareholders, directors, officers, employees
or agents of the Sellers shall be liable under this Agreement and all parties
hereto shall look solely to the Sellers' assets for the payment of any claim or
for the performance of any obligation of the Sellers as a party to this
Agreement.

         26.       BROKERAGE.

         Each party hereto represents and warrants to the other that it has
dealt with no brokers or finders in connection with this transaction and that no
broker, finder or other party is entitled to a commission, finder's fee or other
similar compensation as a result hereof, except Legg Mason Real Estate Services,
Inc. under separate agreement with Buyer. Buyer shall pay to Legg Mason Real
Estate Services, Inc. the compensation payable to it with respect to this
transaction. Sellers hereby indemnify, protect and defend and hold Buyer
harmless from and against all losses, claims, costs, expenses, damages
(including, but not limited to, attorneys' fees of counsel selected by Buyer)
resulting or arising from the claims of any broker, finder or other such party,
claiming by, through or under the acts or agreements of any Seller. Buyer hereby
indemnifies, defends and holds each Seller harmless from and against all losses,
claims, costs, expenses, damages (including, but not limited to, attorneys' fees
of counsel selected by such Seller) resulting or arising from the claims of any
broker, finder or other such party claiming by, through or under acts or
agreements of Buyer. This Section 26 shall survive any termination of this
Agreement and the Closing, if applicable.

         27.       REASONABLE EFFORTS.

         Sellers and Buyer shall use their reasonable, diligent and good faith
efforts, and shall cooperate with and assist each other in their efforts, to
obtain any and all consents and approvals of third parties (including, but not
limited to, governmental authorities) to the transaction contemplated hereby,
and to otherwise perform as may be necessary or otherwise reasonably requested
by the other party to effectuate and carry out the purposes of, this Agreement.


                                       59

<PAGE>

         28.       MISCELLANEOUS.

                  28.1. Entire Agreement. This Agreement, the Services Company
Agreement, and the two option agreements described above constitute the entire
understanding between the parties with respect to the transaction contemplated
herein, and all prior or contemporaneous oral agreements, understandings,
representations and statements, and all prior written agreements,
understandings, letters of intent and proposals are merged into this Agreement.
Neither this Agreement nor any provisions hereof may be waived, modified,
amended, discharged or terminated except by an instrument in writing signed by
the party against which the enforcement of such waiver, modification, amendment,
discharge or termination is sought, and then only to the extent set forth in
such instrument.

                  28.2. Time of the Essence. Time is of the essence of this
Agreement. If any date herein set forth for the performance of any obligations
by Sellers or Buyer or for the delivery of any instrument or notice as herein
provided should be on a Saturday, Sunday or legal holiday, the compliance with
such obligations or delivery shall be deemed acceptable on the next business day
following such Saturday, Sunday or legal holiday. As used herein, the term
"legal holiday" means any state or federal holiday for which financial
institutions or post offices are generally closed in the State of Maryland for
observance thereof.

                  28.3. Conditions Precedent. 28.3.1 The obligations of Buyer to
make the payments and deliver the Shares as described in Section 3 above and to 
close the transaction contemplated herein are subject to the express Buyer's
Conditions Precedent set forth in this Agreement, each of which is for the sole
benefit of Buyer and may be waived at any time by written notice thereof from
Buyer to Seller. The waiver of any particular Buyer's Condition Precedent shall
not constitute the waiver of any other.


                  28.3.2  The obligations of Sellers to close the transaction 
contemplated herein are subject to the express Sellers' Condition Precedent set
forth in this Agreement, each of which is for the sole benefit of Sellers and 
may be waived at any time by written notice thereof from Sellers to Buyer.  The
waiver of any particular Sellers' Condition Precedent shall not constitute the
waiver of any other.


                  28.4. Construction. This Agreement shall not be construed more
strictly against one party than against the other merely by virtue of the fact
that it may have been prepared by counsel for one of the parties, it being
recognized that both Sellers and Buyer have contributed substantially and
materially to the preparation of this Agreement. The headings of various
Sections in this Agreement are for convenience only, and are not to be utilized
in construing the content or meaning of the substantive provisions hereof.

                  28.5. Governing Law.  This Agreement shall be governed by and
construed in accordance with the laws of the State of Maryland.

                  28.6. Partial Invalidity. The provisions hereof shall be
deemed independent and severable, and the invalidity or partial invalidity or
enforceability of any one provision shall not affect the validity of
enforceability of any other provision hereof.

                  28.7. Expenses. Except and to the extent as otherwise
expressly provided to the contrary herein, Buyer and Sellers shall each bear its
own respective costs and expenses relating to the transactions contemplated
hereby, including, without limitation, fees and 

                                       60

<PAGE>

expenses of legal counsel or other representatives for the services used, hired
or connected with the proposed transactions mentioned above.

                  28.8. Control of Defense Counsel. Each indemnified party shall
give reasonably prompt notice to each indemnifying party of any action or
proceeding commenced against the indemnified party in respect of which indemnity
may be sought hereunder, but failure so to notify an indemnifying party (i)
shall not relieve it from any liability which it may have under any indemnity
provided herein unless and to the extent it did not otherwise learn of such
action and the lack of notice by the indemnified party results in the forfeiture
by the indemnifying party of substantial rights and defenses and (ii) shall not,
in any event, relieve the indemnifying party from any obligations to any
indemnified party hereunder other than its indemnification obligation if the
indemnifying party so elects within a reasonable time after receipt of such
notice, the indemnifying party may assume the defense of such action or
proceeding at such indemnifying party's own expense with counsel chosen by the
indemnifying party; provided, however, that, if such indemnified party or
parties reasonably determine that a conflict of interest exists where it is
advisable for such indemnified party or parties to be represented by separate
counsel or that, upon advice of counsel, there may be legal defenses available
to them which are different from or in addition to those available to the
indemnifying party, then the indemnifying party shall not be entitled to one
separate counsel at the indemnifying party's expense. If an indemnifying party
is not so entitled to assume the defense of such action or does not assume such
defense, after having received the notice referred to in the first sentence of
this Section 28.8 , the indemnifying party or parties will pay the reasonable
fees and expenses of counsel for the indemnified party or parties. In such event
however, no indemnifying party will be liable for any settlement effected
without the written consent of such indemnifying party. If an indemnifying party
is entitled to assume, and assumes, the defense of such action or proceeding in
accordance with this Section, such indemnifying party shall not be liable for
any fees and expenses of counsel for the indemnified parties incurred thereafter
in connection with such action or proceeding.

                  28.9. Waiver of Conditions Precedent. Buyer and Sellers shall
each have the right, in its sole and absolute discretion, to waive any Condition
Precedent for its benefit contained in this Agreement.

                  28.10. Certain Securities Matters.  No sale of Shares is
intended by the parties by virtue of their execution of this Agreement.

                  28.11. Counterparts. This Agreement may be executed in any
number of identical counterparts, any of which may contain the signatures of
less than all parties, and all of which together shall constitute a single
agreement.

                  28.12. Calculation of Time Periods. Notwithstanding anything
to the contrary contained in this Agreement, any period of time provided for in
this Agreement that is intended to expire on or prior to the Closing Date, but
that would extend beyond the Closing Date if permitted to run its full term,
shall be deemed to expire upon the Closing.

                                       61

<PAGE>


         IN WITNESS WHEREOF, the parties hereto, intending to be legally bound,
have executed this Acquisition Agreement on the date first above written.

                                  Buyer:


                                  CORPORATE OFFICE PROPERTIES, L.P.

                                  By:   Corporate Office Properties
                                        Trust, its sole general partner


                                  By:_________________________________
                                  Clay W. Hamlin, III, President 
                                  and Chief Executive Officer




                                       62

<PAGE>





<PAGE>


                               JOINDER BY ESCROWEE

         Commonwealth Land Title Insurance Company, intending to be legally
bound, joins in this Agreement to evidence its agreement to act as Escrowee
under this Agreement and to be bound by the provisions of this Agreement
applicable to Escrowee.

                                      COMMONWEALTH LAND TITLE INSURANCE COMPANY


                                      By: ______________________________
                                      Name:
                                      Title:



<PAGE>


                              SCHEDULE OF EXHIBITS

         Exhibit "Sellers"
         Exhibit "Net Value Percentage Allocation"
         Exhibit "Entities"
         Exhibit "Registration Rights Agreement"
         Exhibit "Projects"
         Exhibit "Share Schedule"
         Exhibit "Cash Component Allocation" Exhibit "Assumed Indebtedness"
         Exhibit "Satisfied Indebtedness" Exhibit "Investor Materials" Exhibit
         "Certification of Default" Exhibit "Informational Materials" Exhibit
         "Seller's Deliveries" Exhibit "Permitted Exceptions" Exhibit "Service
         Contracts" Exhibit "Real Estate Tax Matters" Exhibit "Lease
         Controversies" Exhibit "Assumed Loan Documents" Exhibit "Satisfied Loan
         Documents" Exhibit "Tred Avon Loan Documents" Exhibit "Securities
         Reporting Requirements" Exhibit "Audit Representation Letter" Exhibit
         "USTs" Exhibit "Tenant Estoppel Certificate" Exhibit "Option Projects"
         Exhibit "Tenant Purchase Rights" Exhibit "Constellation Lease " Exhibit
         "TIF Agreement" Exhibit "Commissions" Exhibit "Development Management
         Agreement"


<PAGE>


                                EXHIBIT "SELLERS"



<PAGE>


                    EXHIBIT "NET VALUE PERCENTAGE ALLOCATION"



<PAGE>


                               EXHIBIT "ENTITIES"



<PAGE>


                     EXHIBIT "REGISTRATION RIGHTS AGREEMENT"



<PAGE>


                               EXHIBIT "PROJECTS"



<PAGE>


                          EXHIBIT "CONSTELLATION LEASE"



<PAGE>


                            EXHIBIT "SHARE SCHEDULE"



<PAGE>


                       EXHIBIT "CASH COMPONENT ALLOCATION"



<PAGE>


                         EXHIBIT "ASSUMED INDEBTEDNESS"



<PAGE>


                        EXHIBIT "ASSUMED LOAN DOCUMENTS"



<PAGE>


                        EXHIBIT "SATISFIED INDEBTEDNESS"



<PAGE>


                       EXHIBIT "SATISFIED LOAN DOCUMENTS"



<PAGE>


                       EXHIBIT "TRED AVON LOAN DOCUMENTS"



<PAGE>


                          EXHIBIT "INVESTOR MATERIALS"

                        CORPORATE OFFICE PROPERTIES TRUST

                             INVESTOR QUESTIONNAIRE

          ---------------------------------------------------------------------

             ALL INFORMATION HEREIN WILL BE TREATED CONFIDENTIALLY UNLESS
               REQUIRED BY COURT ORDER OR OTHERWISE REQUIRED BY THE
                 CORPORATE OFFICE PROPERTIES TRUST (THE "REIT")
             TO DEMONSTRATE THE AVAILABILITY OF EXEMPTIONS FROM THE
          REGISTRATION REQUIREMENTS OF RELEVANT FEDERAL AND STATE LAWS GOVERNING
                 THE OFFER AND SALE OF THE SECURITIES.
          --------------------------------------------------------------------


Corporate Office Properties Trust
One Logan Square - Suite 1105
Philadelphia, PA   19103

Ladies and Gentlemen:

         The information contained herein is being furnished to you in order for
you to determine whether (i) the undersigned may receive Common Shares and
Convertible Preferred Shares of the REIT (collectively, the "Securities") as
contemplated by the Acquisition Agreement between Corporate Office Properties,
L.P. (the "UPREIT") and the other signatories thereto with respect to the
acquisition of the Interests in the entities owning the portfolio of
Constellation Real Estate, Inc., Columbia, Maryland (the "Agreement"), and (ii)
the undersigned's subscription for the Securities as evidenced by the execution
of the Agreement may be accepted by you in accordance with the requirements of
Section 4(2) of the Securities Act of 1933, as amended (the "Act"), and
Regulation D promulgated thereunder ("Regulation D"). The undersigned
understands that you will rely on the information contained herein for purposes
of, among other things, determining whether the undersigned is an "Accredited
Investor" as such term is defined in Regulation D. The undersigned also
understands that this Questionnaire is not an offer of the Securities or any
other securities to the undersigned.

         The undersigned understands that its answers will at all times be kept
confidential unless required by court order or otherwise required by the REIT or
UPREIT to demonstrate the availability of exemptions from the registration
requirements of relevant federal and state laws governing the offer and sale of
the Securities. By signing this Investor Questionnaire, the undersigned agrees
that the REIT may present this Investor Questionnaire to such parties as either
deems appropriate if called upon under law to establish the availability under
federal or state laws of an exemption from registration of the offer and sale of
the Securities.

                                                    -----------

                                  INSTRUCTIONS

         (A) Complete either Section I or Section II, whichever is applicable,
on pages 3-7.

<PAGE>

         (B)      On page 8, date and sign where indicated. If the investor is a
                  corporation, a Notary Public must complete and sign on page 9.

         Please print or type your answers. If the answer to any question is
"No" or "Not Applicable," please so state. Please provide information for every
investor, using a separate questionnaire for each. Please do not confuse
individual assets or income with assets or income of a trust, corporation or
partnership in which you have an interest; do, however, list the value of your
interest in such entities.


                       INDIVIDUALS MUST COMPLETE SECTION I
                                       AND
             CORPORATIONS, ENTITIES AND OTHER ENTITIES MUST COMPLETE
                                   SECTION II

                   ALL QUESTIONS IN THE APPROPRIATE SECTION MUST BE ANSWERED -


SECTION I.        QUESTIONS FOR INDIVIDUALS

         1.       Name:______________________________________  Age:____________

U.S. Citizen:     Yes_____ No_____

Number of Dependents:_____ Social Security No.:_________________________________

         2. Are you acquiring the Securities of the UPREIT for your own account?

                                                      Yes_____         No_____

                  If no, please specify:

         3. Method of Investment Qualification: An individual will qualify as an
Accredited Investor if he or she meets any one of the following requirements.
Please indicate if you meet any of the following requirements:

         (A)      I am a natural person and had an individual income in excess
                  of $200,000 in each of the two most recent years and
                  reasonably expect an income in excess of $200,000 in the
                  current year. For these purposes, "income" means my individual
                  adjusted gross income for federal income tax purposes, plus
                  (i) any deduction for long term capital gains; (ii) any
                  deduction for depletion; (iii) any exclusion for interest; and
                  (iv) any losses of a partnership allocated to an individual
                  limited partner.

                                                      Yes_____         No_____

                                       2
<PAGE>

         (B)      I am a natural person and had a joint income with my spouse in
                  excess of $300,000 in each of the two most recent years and
                  reasonably expect a joint income with my spouse in excess of
                  $300,000 in the current year. For these purposes, "income"
                  shall be determined as set forth in Section 3(A) above.

                                                      Yes_____         No_____

         (C)      I am a natural person and had an individual net worth on the
                  date hereof (or joint net worth with my spouse) in excess of
                  $1 million (including my home, home furnishings and
                  automobiles).

                                                      Yes_____         No_____

         (D) I am a director, executive officer or general partner of the REIT.

                                                      Yes_____         No_____

I understand that the UPREIT and the REIT will rely upon the accuracy and
completeness of my responses to the foregoing questions and I represent and
warrant to the UPREIT and the REIT as follows:

         (a)      The answers to the above questions are complete and correct
                  and may be relied upon by the UPREIT and the REIT in
                  determining whether the undersigned is an Accredited Investor.

         (b)      I will immediately notify the UPREIT and the REIT of any
                  material change in any statement made herein occurring prior
                  to the closing of any subscription for the Securities.

         (c)      The acquisition of the Securities will be solely for my
                  account, and not for the account of any other person or with a
                  view toward transfer, resale, assignment, fractionalization or
                  distribution thereof.

SECTION II.       QUESTIONS FOR CORPORATIONS, ENTITIES AND OTHER ENTITIES

         1.       Name and Nature (e.g., limited partnership, corporation,
                  trust, limited liability company) of Entity:

         2.       Date of Organization:

         3.       State of Organization:

         4.       Taxpayer Identification No.:

         5.       Accredited Investor Suitability Requirements.

         (A) Has the subscribing entity been formed for the specific purpose of
investing in the Securities?

                                                      Yes_____         No_____

                                       3

<PAGE>

         (B)      If your answer to question A is "No," INITIAL OR CHECK
                  whichever of the following statements is applicable to the
                  subscribing entity; if your answer to question A is "Yes" or
                  if none of the statements in clause (1) below is applicable,
                  the subscribing entity must be able to certify to statement
                  (2) below in order to qualify as an Accredited Investor.

         (1) The undersigned entity certifies that it is an Accredited Investor
because it is:

               (i) a bank as defined in Section 3(a)(2) of the Act, or a
         savings and loan association or other institution as defined in Section
         3(a)(5)(A) of the Act, whether acting in an individual or fiduciary
         capacity;

                                                      Yes_____         No_____

              (ii) a broker or dealer registered pursuant to Section 15 of
 the Securities Exchange Act of 1934;

                                                      Yes_____         No_____

             (iii) an insurance company as defined in Section 2(13) of the Act


                                                      Yes_____         No_____

              (iv)   an investment company registered under the Investment
 Company Act of 1940;

                                                      Yes_____         No_____

               (v)   a business development company as defined in Section 2(a)
(48) of the Investment Company Act of 1940;

                                                      Yes_____         No_____

                  (vi) a Small Business Investment Company licensed by the U.S.
         Small Business Administration under Section 301(c) or (d) of the Small
         Business Investment Act of 1958;

                                                      Yes_____         No_____

                  (vii) a plan established by a state or its political
         subdivisions, or any agency or instrumentality of a state or its
         political subdivisions, for the benefit of its employees provided that
         such employee benefit plan has total assets in excess of $5,000,000;

                                                      Yes_____         No_____
                                       4

<PAGE>

                  (viii) an employee benefit plan within the meaning of the
         Employee Retirement Income Security Act of 1974, provided that the
         investment decision is made by a plan fiduciary, as defined in Section
         3(21) of such Act, and the plan fiduciary is either a bank, insurance
         company or registered investment adviser or provided that the employee
         benefit plan has total assets in excess of $5,000,000 or, if a
         self-directed plan, the investment decisions are made solely by persons
         that are Accredited Investors (if a self-directed plan with more than
         one investment account, (1) each participant must maintain a separate
         investment account within the plan, and (2) the funds of the separate
         investment accounts within the plan must not be commingled);

                                                      Yes_____         No_____

                  (ix) a private business development company as defined in
 Section 202(a)(22) of the Investment Advisers Act of 1940;

                                                      Yes_____         No_____

                  (x) an organization described in Section 501(c)(3) of the
         Internal Revenue Code of 1986, as amended, a corporation, a
         Massachusetts or similar business trust, or partnership, not formed for
         the specific purpose of acquiring the Securities, with total assets in
         excess of $5,000,000; or

                                                      Yes_____         No_____

                  (xi) a trust, with total assets in excess of $5,000,000, not
         formed for the specific purpose of investing in the Securities, whose
         subscription is directed by a sophisticated person as defined in Rule
         506(b)(2)(ii) promulgated under the Act.

                                                      Yes_____         No_____

         (2) The undersigned entity certifies that it is an Accredited Investor
because each of its stockholders, partners or other equity holders meets at
least one of the following conditions:

                  (i) It is a natural person and had an individual net worth at
         the time of subscription for (or joint net worth with spouse) in excess
         of $1 million (including my home, home furnishings and automobiles).

                                                      Yes_____         No_____

                  (ii) It is a natural person and had an individual income
         (without including any income of my spouse) in excess of $200,000 (or
         joint income with my spouse in excess of $300,000) in each of the two
         most recent years and reasonably expect an individual income in excess
         of $200,000 (or joint income with my spouse in excess of $300,000) in
         the current year. For these purposes, "income" means my individual
         adjusted gross income for federal income tax purposes, plus (i) any
         deduction for long term capital gains; (ii) any deduction for
         depletion; (iii) any exclusion for interest; and (iv) any losses of a
         partnership allocated to an individual limited partner.

                                                      Yes_____         No_____

                                       5
<PAGE>


                  (iii) The stockholder, interest holder or other equity holder
         is a corporation, partnership, trust or other entity which meets the
         description of at least one of the organizations specified in statement
         B(1) above or whose stockholders, partners, beneficiaries or other
         equity holders meet at least one of the descriptions in this statement
         B(2).

                                                      Yes_____         No_____

         6. The undersigned entity has all requisite authority to acquire the
Securities referenced in, and to enter into, the Subscription Agreement.

                                                      Yes_____         No_____

The undersigned understands that the UPREIT and the REIT will rely upon the
accuracy and completeness of its responses to the foregoing questions and
represents and warrants to the UPREIT and the REIT as follows:

         (a)      The answers to the above questions are complete and correct
                  and may be relied upon by the UPREIT and the REIT in
                  determining whether the undersigned is an Accredited Investor.

         (b)      The undersigned will immediately notify the UPREIT and the
                  REIT of any material change in any statement made herein
                  occurring prior to the closing of any offering by the
                  undersigned of the Securities.

         (c)      The undersigned is able to bear the economic risk of an
                  investment in the Securities of the size contemplated. In
                  making this statement, consideration has been given to whether
                  the undersigned can afford to hold the investment for an
                  indefinite period of time and whether the undersigned can
                  afford a complete loss of its investment. The undersigned
                  offers as evidence of its ability to bear the economic risk
                  the information contained in this Investor Questionnaire.

         (d)      The acquisition of the Securities will be solely for the
                  undersigned's account, and not for the account of any other
                  person or with a view toward transfer, resale, assignment,
                  fractionalization or distribution thereof.

                                       6
<PAGE>

         IN WITNESS WHEREOF, the undersigned has executed this Investor
Questionnaire this ______ day of _______________, 199___ and declare that it is
truthful and correct.

INDIVIDUALS                               CORPORATIONS, ENTITIES AND
                                          OTHER ENTITIES


Signature of Investor                     Name of Entity


                                          Authorized Signature


PRINT Name of Investor                    PRINT Name and Title of Person Signing

Address:                                  Address:




                                       7
<PAGE>



                      ACKNOWLEDGMENT FOR CORPORATE INVESTOR

STATE OF __________________         )
                                            )        SS
COUNTY OF __________________        )

         On this ______ day of __________________, 199___, before me personally
appeared ____________________________ to me known, who, being first by me duly
sworn, did depose and say that (s)he resides at _____________________________
that (s)he is the ______________ of ________________________, the corporation
described in and which executed the above instrument; that [the corporation has
no seal]* [(s)he knows the seal of said corporation; that the seal affixed to
said instrument is such corporate seal; that it is so affixed by order of the
Board of Directors of said corporation]*, and that (s)he signed his(her) name
thereto by order of said corporation's Board of Directors.

         IN WITNESS WHEREOF, I have hereunto set my hand and affixed my official
seal the day and year in this certificate first above written.

                                       -----------------------------------------
                                                          Notary Public:

                                                       My Commission Expires:

[SEAL]



















- - -------------------------------
*  Strike out whichever bracketed clause does not apply.



<PAGE>


                        EXHIBIT "INFORMATIONAL MATERIALS"

         The following documents filed to date by the REIT with the Securities
and Exchange Commission pursuant to either the Securities Exchange Act of 1934,
as amended or the Securities Act of 1933, as amended:

         1.   Annual Report on Form 10-K for the year ended December 31, 1997;

         2.   Proxy Statement dated February 11, 1998; and,

         3.   Prospectus dated April 22, 1998 included in Registration Statement
Number 333-47465 filed pursuant to Rule 424(b).



<PAGE>


                          EXHIBIT "SELLER'S DELIVERIES"

         1.       Copies of any and all Leases and all other agreements 
affecting the Projects.

         2. A rent roll (the "Rent Roll") indicating all Tenants, spaces
occupied and vacant (including the square footage thereof), Base Rent,
escalations, "pass-throughs" (including, but not limited to, real estate taxes,
utilities, insurance and/or operating expenses), Additional Rent, rent
adjustments (including, but not limited to, Consumer Price Index, or other
adjustments) construction allowances, abatements, concessions, lease
commencement and expiration dates, renewal or expansion options, options to
purchase, cancellation rights, security and/or other deposits.

         3. A schedule of all employees of Sellers engaged in the operation or
maintenance of the Projects or Contributor's business, setting forth in respect
of each employee: such employee's name, position, duties, current salary or
wages, Christmas or other bonus, fringe benefits, accrued vacation time and sick
leave, and information as to any other compensation in cash or in kind to which
such employee may be entitled.

         4. Copies of all hazard, rent loss, liability and other insurance
policies currently in force with respect to the Projects and/or Contributor's
business (the "Existing Insurance Policies").

         5. Copies of all income and expense statements, year-end financial and
monthly and annual operating statements (the "Operating Statements") for the
Projects for calendar years 1995, 1996, 1997 and, to the extent available, 1998.
Sellers shall deliver to Acquiror all Operating Statements prepared in the
ordinary course of business promptly upon preparation thereof relating to
periods prior to Closing, even if prepared after Closing.

         6, Copies of all engineering and architectural plans and
specifications, drawings, studies and surveys relating to the Projects
(collectively the "Plans"), in Contributor's possession or control, and copies
of any reports or studies (including, but not limited to, inspection reports of
governmental authorities or insurance carriers), in Contributor's possession or
control, in respect of the physical condition or operation of the Projects or
recommended improvements thereto.

         7. Copies of the bill or bills issued for the years 1995, 1996, 1997
and, if available, 1998, for all real estate taxes and personal property taxes
and copies of any and all notices pertaining to real estate taxes or assessments
applicable to the Projects (the "Tax Bills"). Sellers shall promptly deliver to
Acquiror copies of any such bills or notices received by Sellers after the
Contract Date, even if received after Closing.

         8. Copies of all brokerage commission, management, leasing,
maintenance, repair, service, pest control and supply contracts (including,
without limitation, janitorial, elevator, scavenger, laundry and landscaping
agreements), equipment rental agreements and master antenna agreements (if
applicable), and any other contracts or agreements relating to or affecting the
Projects (other than Major Repair Contracts, as defined herein) or which will be
binding upon the Projects or Acquiror subsequent to Closing, all as amended (the
"Contracts").

<PAGE>

         9. Copies of all contracts for repairs or capital replacements to be
performed at the Projects, or covering such work performed during the two (2)
years immediately preceding the Contract Date for a contract price in excess of
$10,000.00 "Major Repair Contracts").

         10. Copies of all certificates of occupancy, licenses, permits,
authorizations and approvals required by law or by any governmental authority
having jurisdiction thereover in respect of the Projects, or any portion
thereof, occupancy thereof or any present use thereof (the "Governmental
Approvals").

         11. Copies of any operating budgets for the Projects for the years
1996, 1997, and 1998.

         12. Copies of the documents pursuant to which Sellers is organized and
operates its business, together with proof of the authority of the signatory or
signatories of this Agreement on behalf of Sellers to execute this Agreement.

         13. Copies of all guarantees, warranties and other documents or
instruments evidencing or relating to the Intangible Personal Property.

         14. Copies of all unrecorded easements and licenses of Sellers for the
benefit of any Project or portion thereof or of third parties burdening any
Project or portion thereof.

         15. Copies of all of the organizational documents pertaining to each
Entity (including all partnership agreements, as amended, certificates of
limited partnership and any other documents pertaining to the organization,
operation or management of each Entity).

         16. Copies of all of the Existing Loan Documents (as defined in the
body of this Agreement) and any correspondence or notices pertaining thereto.

                                       2

<PAGE>


                        EXHIBIT "TENANT PURCHASE RIGHTS"



<PAGE>


                           EXHIBIT "SERVICE CONTRACTS"



<PAGE>


                        EXHIBIT "REAL ESTATE TAX MATTERS"



<PAGE>


                          EXHIBIT "LEASE CONTROVERSIES"



<PAGE>


                   EXHIBIT "SECURITIES REPORTING REQUIREMENTS"

         For the period of time commencing on the date of the Acquisition
Agreement and continuing through the second anniversary of the Closing Date,
Sellers shall, from time to time, upon reasonable advance notice from the REIT,
provide the REIT and its representatives, agents and employees with access to
all financial and other information in its possession or with respect to which
it has reasonable access pertaining to the period of Seller's ownership and
operation of the Projects, which information is relevant and reasonably
necessary, in the opinion of the REIT's outside, third party accountants (the
"Accountants"), to enable the REIT and its Accountants to prepare financial
statements in compliance with any or all of (a) Rule 3-14 of Regulation S-X of
the Securities and Exchange Commission (the "Commission"); (b) any other rule
issued by the Commission and applicable to the REIT; and (c) any registration
statement, report or disclosure statement filed with the Commission by, or on
behalf of, the REIT; provided, however, that in any such event(s), the UPREIT
shall reimburse Sellers for those third party, out-of-pocket costs and expenses
that Sellers incur in order to comply with the foregoing requirements. Sellers
acknowledge and agree that the following is a representative description of the
information and documentation that the REIT and the Accountants may require in
order to comply with (a), (b) and (c) above. Sellers shall provide such
information, and documentation on a per-Project basis, if available.

         1. Rent rolls for the calendar month in which the Closing occurs and
the eleven (11) calendar months immediately preceding the calendar month in
which the Closing occurs;

         2. Seller's written analysis of both (a) scheduled increases in base
rent required under any Leases in effect on the Closing Date; and (b) rent
concessions imposed those Leases, and the straight line effect of (a) and (b);

         3. Seller's internally-prepared Operating Statements;

         4. Access to Leases;

         5. Seller's budgeted annual and monthly income and expenses, compared
to actual annual and monthly income and expenses;

         6. Most currently available real estate tax bills;

         7. Access to Seller's cash receipt journal(s) and bank statements for
the Projects;

         8. Seller's general ledger with respect to the Projects;

         9. Seller's schedule of expense reimbursements required under Leases in
effect on the Closing Date;

<PAGE>

         10. Schedule of those items of repairs and maintenance performed by, or
at the direction of Seller, during Seller's final fiscal year in which Seller
owns and operates the Projects (the "Final Fiscal Year");

         11. Schedule of those capital improvements and fixed asset additions
made by, or at the direction of, Seller during the Final Fiscal Year;

         12. Access to Seller's invoices with respect to expenditures made
during the Final Fiscal Year; and

         13. Access (during normal and customary business hours) to responsible
personnel to answer accounting questions.



<PAGE>


                      EXHIBIT "AUDIT REPRESENTATION LETTER"

[Date]

Dear Sirs:

         We are writing at your request to confirm our understanding that your
audit of the statement of operating income for the year ended
_____________________, ______, was made for the purpose of expressing an opinion
as to whether the statement of operating income presents fairly, in all material
respects, the results of operations of [Name of Project] in conformity with
generally accepted accounting principles. In connection with your audit we
confirm, to the best of our knowledge and belief, the following representations
made during your audit.

         1. All financial records, board minutes and data related to the
property have been made available to you.

         2. There have been no:

                  (a) Irregularities involving any member of management or
employees who have significant roles in the system of internal accounting
control structure.

                  (b) Irregularities involving other employees that could have a
material effect on the financial statements.

                  (c) Communications from regulatory agencies concerning
noncompliance with, or deficiencies in, financial reporting practices that could
have a material effect on the financial statements.

                  (d) Violations or possible violations of laws or regulations,
the effects of which should be considered for disclosure in the financial
statements or as a basis for recording a loss contingency.

         3. There are no:

                  (a) Unasserted claims or assessments that are probable of
assertion and must be disclosed in accordance with Statement of Financial
Accounting Standards No. 5.

                  (b) Material liabilities or gain or loss contingencies
(including oral and written guarantees) that are required to be accrued or
disclosed by Statement of Financial Accounting Standards No. 5.

                  (c) Material transactions that have not been properly recorded
in the accounting records underlying the financial statements.

<PAGE>

                  (d) Events that have occurred subsequent to
___________________, ___________ in the financial statements that would require
adjustment to or disclosure in the financial statements, except for the sale
which you are aware of.

         4. Appropriate adjustment, when material, has been made for:

                  (a)      Uncollectible amounts recorded under lease contracts.

                  (b)      Rental income received in advance.

                  (c)      Rent concessions, abatements, or rent holidays.

         5. The Company has complied with all aspects of contractual agreements
that would have a material effect on the financial statements in the event of
noncompliance.

         6. All significant related party transactions have been properly
recorded or disclosed in the financial statements.

         7. In the opinion of the undersigned the ____________ and _____________
financial information provided to you contains all adjustments necessary for a
fair presentation of operating income.

                                                     By:


                                                     [Seller/Seller's Manager]


<PAGE>


                                 EXHIBIT "USTS"



<PAGE>


                      EXHIBIT "TENANT ESTOPPEL CERTIFICATE"

To:

                             (Lease to be Attached)

         The undersigned, ______________________________________ ("Tenant"),
hereby certifies that:

                  (a) Annexed hereto as Exhibit "A" is a true and correct copy
of the lease ("Lease"), dated as of the _____ day of _______________, 19___, by
and between the undersigned, as tenant ("Tenant"), and
_____________________________________________ as landlord ("Landlord"), covering
certain [insert type of property] space ("Premises") in the building located at
_________________________________ ("Building"). The net rentable square footage
of the Premises is ________________________.

                  (b) The Lease is valid and in full force and effect on the
date hereof. The term of the Lease commenced on ____________, 19___, and the
termination date of the present term of the Lease, excluding renewals, is
__________________, 19___.

                  (c) There are no other agreements between Landlord and Tenant
with respect to the Premises.

                  (d) There are no uncured defaults on the part of Tenant or on
the part of Landlord under the Lease, and no event has occurred and no condition
exists which, with the giving of notice or the lapse of time, or both, will
constitute a default under the Lease.

                  (e) Fixed Rent payable by Tenant presently is $______________
per month and no such rent has been paid more than thirty (30) days in advance
of its due date. Tenant's security deposit is
$---------------.

                  (f) Additional Rent (including Tenant's share of tax increases
and cost of living increases) payable by Tenant presently is $______________ per
month and no such rent has been paid more than thirty (30) days in advance of
its due date.

                  (g) Tenant claims no present charge, lien or claim of offset
under the Lease or otherwise, against rents or other charges due or to become
due thereunder.

                  (h) Tenant has accepted possession of the Premises and any
improvements required by the terms of the Lease to be made by the lessor
thereunder have been completed to the satisfaction of Tenant.

                  (i) The address for notices to be sent to Tenant is as set 
forth in the Lease.

<PAGE>

                  (j) This Estoppel Certificate may be relied upon by any
prospective purchaser or encumbrancer of the Building.

                  (k) Tenant has no right of first refusal, option or other
right to purchase the Premises or the Building, nor does Tenant have any right
to unilaterally cancel the Lease. Tenant has no renewal options or expansion
options.

                  (l) Rents payable pursuant to the Lease are not based upon the
income or profits of Tenant.

                  (m) There is not a material amount of personal property
demised to the Tenant under or in connection with the Lease.

                  (n) Except for services customarily provided by landlords in
the geographic area of the Premises, there are no services furnished to the
Tenant in connection with the lease of the Premises.

                  (o) The Lease was not entered into in connection with a sale/
leaseback transaction.

                  (p) There are no subleases under or in connection with the 
Lease.

         IN WITNESS WHEREOF, the undersigned has executed and delivered this
Estoppel Certificate on the _____ day of ______________, 19____.


                                          ------------------------------------
                                                           (Tenant)

                                         By:      ______________________________


                                       2
<PAGE>


- - -ii-
371015.6 9/4/98
371015.6 9/4/98
                       EXHIBIT "CERTIFICATION OF DEFAULT"

                     [CONSTELLATION REAL ESTATE LETTERHEAD]

                                   [DATE]

VIA FEDERAL EXPRESS

Commonwealth Land Title Insurance Company
1700 Market Street
Philadelphia, PA   19103
Attention:  M. Gordon Daniels, Esquire

  Re: Certification of Default under that certain Contribution Agreement dated
      as of May ____, 1998 for the Constellation Real Estate Portfolio/Completed
      Properties

Dear Mr. Daniels:

         Commonwealth Land Title Insurance Company ("Escrowee") is the escrow
agent under the Contribution Agreement described above (the "Contribution
Agreement"). In such capacity, Escrowee is presently holding that certain
$5,000,000 letter of credit issued by ____________________ (the "Issuer") for
the benefit of Escrowee (the "Letter of Credit") in escrow under and subject to
the terms of the Contribution Agreement. Capitalized terms which are not
otherwise defined in this letter shall have the meaning set forth in the
Contribution Agreement.

         You are hereby advised, and the undersigned hereby certifies, that
Buyer has defaulted in the performance of Buyer's obligations under the
Contribution Agreement by __________________________________ [INSERT HERE
DETAILED DESCRIPTION OF NATURE OF ALLEGED DEFAULT]. As required by Section 6.3.1
of the Contribution Agreement, you are hereby directed to submit a draft on the
Letter of Credit in the amount of $5,000,000 to the Issuer, and to hold such
Proceeds in escrow in accordance with the terms of the Contribution Agreement in
a separate, interest bearing, money market account in a federally insured bank.


<PAGE>

         This notice constitutes a Certification of Default as defined in the
Contribution Agreement.

                              [INSERT SIGNATURE BLOCK; MUST BE 
                              SIGNED BY RANDALL M. GRIFFIN,
                              JOHN HARRIS GURLEY,
                              CHARLES E. GARMAN OR
                              DAN R. SKOWRONSKI AND NOTARIZE]

cc:      Clay W. Hamlin, III (via Federal Express)
         F. Michael Wysocki, Esquire (via Federal Express)


<PAGE>


STATE OF MARYLAND

COUNTY OF ____________________

         On this _____ day of __________, 1998, before me, the undersigned
officer, personally appeared ____________________________, known to me (or
satisfactorily proven) to be the person who executed the Certification of
Default and acknowledged that he is the _______________________ of
___________________________ and that he executed the same for the purposes
therein contained on behalf of the corporation by signing his name as such
officer.

         IN WITNESS WHEREOF, I have hereunto set my hand and affixed my official
seal.


                                        ------------------------------------
                                                  Notary Public



<PAGE>


                            EXHIBIT "OPTION PROJECTS"

         All documents listed below are attached.

         1.       National Business Park
                  5 Year Option and Right of First Refusal

         2.       Brown's Wharf adjacent land - Right of First Refusal

         3.       Constellation Centre Unit 6 and 2 - Right of First Refusal

         4.       Annapolis Exchange
                  2 Year Option to Purchase (LLC Member interests)



<PAGE>


                              EXHIBIT "COMMISSIONS"



<PAGE>


                                TABLE OF CONTENTS

                                                                          Page


1. DEFINITIONS.................................................................3


2. ASSIGNMENT AND TRANSFER OF INTERESTS.......................................10


3. CONSIDERATION..............................................................10


4. SHARES; INVESTOR MATERIALS; PROXY STATEMENT................................13


5. REIT BOARD OF TRUSTEES; CERTAIN REIT OPERATIONS; RELATED TRANSACTIONS......14


6. CLOSING....................................................................16


7. SELLER'S DELIVERIES........................................................19


8. INSPECTION PERIOD..........................................................19


9. TITLE AND SURVEY MATTERS...................................................21


10. REPRESENTATIONS AND WARRANTIES AS TO PROJECTS.............................22


11. REPRESENTATIONS AS TO INTERESTS/SECURITIES AND RELATED MATTERS............27


12. COVENANTS OF SELLER.......................................................31


13. ENVIRONMENTAL WARRANTIES AND AGREEMENTS...................................35


14. ADDITIONAL CONDITIONS PRECEDENT TO CLOSING................................38

15. LEASES-CONDITIONS PRECEDENT AND WARRANTIES WITH RESPECT THERETO...........40


16. CLOSING DELIVERIES........................................................42


17. PRORATIONS AND ADJUSTMENTS................................................47


18. CLOSING EXPENSES..........................................................50


19. DESTRUCTION, LOSS OR DIMINUTION OF PROJECTS...............................50


20. DEFAULT...................................................................52


21. SUCCESSORS AND ASSIGNS....................................................54


22. LITIGATION................................................................55


23. NOTICES...................................................................55


24. BENEFIT...................................................................56

<PAGE>


25. LIMITATION OF LIABILITY...................................................56


26. BROKERAGE.................................................................57


27. REASONABLE EFFORTS........................................................57

28. MISCELLANEOUS.............................................................57




                    FIRST AMENDMENT TO CONTRIBUTION AGREEMENT

         THIS FIRST AMENDMENT TO CONTRIBUTION AGREEMENT ("First Amendment") is
made and executed as of this 16th day of July, 1998 by and between CORPORATE
OFFICE PROPERTIES TRUST and CORPORATE OFFICE PROPERTIES, L.P. (collectively, the
"Buyer") and the Sellers listed on the signature page to this First Amendment
and defined in the Contribution Agreement (collectively, the "Sellers" and each
individually, a "Seller").

         A. Sellers and Buyer entered into a Contribution Agreement dated May
14, 1988 pursuant to which Sellers agreed to contribute a property known as
Brandon and certain interests in Entities which own certain real estate and a
mortgage in Maryland to the Buyer in exchange for cash, the assumption of
certain debt, and Common Shares and Convertible Preferred Shares (the
"Contribution Agreement"). Capitalized terms used, but not defined, in this
First Amendment shall have the meanings given to such terms in the Contribution
Agreement.

         B. Sellers and Buyer desire to amend the Contribution Agreement as set
forth in this First Amendment.

         NOW, THEREFORE, in consideration of the agreements contained herein and
intending to be legally bound hereby, Sellers and Buyer agree as follows:

                  1. Section 6.1 of the Contribution Agreement is hereby deleted
in its entirety and the following Section 6.1 is substituted in its place:

           "6.1     First Closing.  The assignment and transfer of the
                    Interests, the conveyance of Brandon, and the other
                    transactions contemplated herein with respect to all Sellers
                    except the NBP 135 Sellers and the Woodlands Sellers (the
                    "First Closing") shall be consummated on the date (the
                    "First Closing Date"), after the shareholders of the REIT
                    have approved all of the transactions contemplated by this
                    Agreement, specified by Buyer on not less than seven (7)
                    days notice to Sellers (the "Buyer's Closing Notice"),
                    provided that the First Closing Date shall not be sooner
                    than September 14, 1998, unless mutually agreed upon by
                    Sellers and Buyer, or later than forty-five (45) days after
                    the shareholders of the REIT have approved all of the
                    transactions contemplated by this Agreement.  Sellers shall
                    have the right to postpone the First Closing to a date that
                    is up to five (5) days after the First Closing Date
                    specified in Buyer's



                                       
<PAGE>


                    Closing Notice by giving Buyer notice
                    of such postponement.  If the shareholders of the REIT have
                    not approved the transactions contemplated by this Agreement
                    by October 30, 1998, this Agreement shall terminate and
                    become null and void, the Letter of Credit shall be returned
                    to the Buyer, and the parties shall be released from all
                    liability or obligation to the other.  The Closing shall
                    take place at the offices of Saul, Ewing, Remick & Saul LLP,
                    Centre Square West, 1500 Market Street, 38th Floor,
                    Philadelphia, Pennsylvania 19102, or at such other place as
                    may mutually agreed upon by the parties.

                  2. This First Amendment may be executed in counterparts, each
of which shall constitute an original, but all of which together shall
constitute one and the same document. Delivery of executed copies of this First
Amendment by facsimile transmission shall be deemed effective to amend the
Agreement. Each party transmitting such facsimile agrees to promptly deliver an
original executed copy of this First Amendment to the other party by recognized
overnight courier.

                  3. As amended by this First Amendment, the Contribution
Agreement shall remain in full force and effect.

                     [SIGNATURES APPEAR ON FOLLOWING PAGES]


                                       2

<PAGE>



         IN WITNESS WHEREOF, and intending to be legally bound hereby, Sellers
and Buyer have executed this First Amendment on the day and year first above
written.

                                     BUYER:

                                     CORPORATE OFFICE PROPERTIES, L.P.

                                     By: Corporate Office Properties Trust,
                                         its sole general partner


                                     By:    /s/ Clay W. Hamlin, III
                                             Clay W. Hamlin, III
                                         President and Chief Executive Officer

WITNESS                             SELLERS:

                                    CONSTELLATION PROPERTIES, INC., a Maryland
                                    corporation


    /s/ Roger Waesche, Jr.         By:   /s/ Randall M. Griffin
                                          Randall M. Griffin
                                               President

                                    NBP-I LIMITED PARTNERSHIP, a Maryland
                                    limited partnership

                                    By: Constellation Properties, Inc.,
                                        a Maryland corporation, General Partner


    /s/ Roger Waesche, Jr.         By:     /s/ Randall M. Griffin
                                               Randall M. Griffin
                                                   President

                       [SIGNATURES CONTINUED ON NEXT PAGE]

                                       3

<PAGE>


                                     NBP-II LIMITED PARTNERSHIP, a Maryland 
                                     limited partnership

                                     By: Constellation Properties, Inc.,
                                         a Maryland corporation, General Partner


    /s/  Roger Waesche, Jr.          By:   /s/ Randall M. Griffin
                                             Randall M. Griffin
                                                  President

                                     NBP-IV, LLC, a Maryland limited liability
                                     company

                                     By: CPI National Business Park, IV, Inc.,
                                         a Maryland corporation, Member


    /s/  Roger Waesche, Jr.          By:    /s/ Randall M. Griffin
                                            Randall M. Griffin
                                                 President

                                     ST. BARNABAS LIMITED PARTNERSHIP,
                                     a Maryland limited partnership

                                     By: Constellation Properties, Inc.,
                                         a Maryland corporation, General Partner


    /s/  Roger Waesche, Jr.          By:    /s/ Randall M. Griffin
                                            Randall M. Griffin
                                                 President

                                     By:      CPO Constellation Centre, Inc.,
                                              a Maryland corporation,
                                              General Partner


    /s/  Roger Waesche, Jr.          By:       /s/ Randall M. Griffin
                                                 Randall M. Griffin
                                                     President

                       [SIGNATURES CONTINUED ON NEXT PAGE]

                                       4

<PAGE>


                                   LAUREL TOWER ASSOCIATES LIMITED PARTNERSHIP, 
                                   a Maryland limited partnership

                                   By:  Constellation Properties, Inc.,
                                        a Maryland corporation, General Partner


    /s/  Roger Waesche, Jr.        By:       /s/ Randall M. Griffin
                                               Randall M. Griffin
                                                    President

                                   By:  CPO Laurel Towne, Inc.,
                                        a Maryland corporation, General Partner


    /s/ Roger Waesche, Jr.         By:        /s/ Randall M. Griffin
                                              Randall M. Griffin
                                                    President

                                   THREE CENTRE PARK ASSOCIATES LIMITED
                                   PARTNERSHIP, a Maryland limited partnership

                                   By: Constellation Properties, Inc., 
                                       a Maryland corporation, General Partner


    /s/  Roger Waesche, Jr.        By:     /s/ Randall M. Griffin
                                              Randall M. Griffin
                                                   President

                                   By: CPO Three Centre Park, Inc., a Maryland
                                       corporation, General Partner


    /s/  Roger Waesche, Jr.        By:       /s/ Randall M. Griffin
                                              Randall M. Griffin
                                                   President

                       [SIGNATURES CONTINUED ON NEXT PAGE]

                                       5

<PAGE>


                                   BROWN'S WHARF LIMITED PARTNERSHIP, a Maryland
                                   limited partnership

                                   By: Constellation Properties, Inc.,
                                       a Maryland corporation, General Partner


    /s/  Roger Waesche, Jr.        By:      /s/ Randall M. Griffin
                                             Randall M. Griffin
                                                  President

                                   By: CPI Brown's Wharf, Inc., a Maryland 
                                       corporation, General Partner


    /s/  Roger Waesche, Jr.        By:       /s/ Randall M. Griffin
                                                Randall M. Griffin
                                                    President

                                   CRANBERRY-140 LIMITED PARTNERSHIP, a Maryland
                                   limited partnership

                                   By:  Constellation Properties, Inc.,
                                        a Maryland corporation, General Partner


    /s/ Roger Waesche, Jr.         By:      /s/ Randall M. Griffin
                                              Randall M. Griffin
                                                  President

                                   TRED LIGHTLY LIMITED LIABILITY COMPANY,
                                   a Maryland limited company

                                   By:  CPI Tred Avon, Inc., a Maryland 
                                        corporation, Member


    /s/  Roger Waesche, Jr.        By:     /s/ Randall M. Griffin
                                           Randall M. Griffin
                                                 President

                       [SIGNATURES CONTINUED ON NEXT PAGE]

                                       6

<PAGE>


                                   CONSTELLATION GATESPRING, LLC, a Maryland
                                   limited partnership

                                   By:  CPI Gatespring, Inc., a Maryland
                                        corporation, Member


    /s/  Roger Waesche, Jr.        By:      /s/ Randall M. Griffin
                                                Randall M. Griffin
                                                    President

                                       7





                   SECOND AMENDMENT TO CONTRIBUTION AGREEMENT

         THIS SECOND AMENDMENT TO CONTRIBUTION AGREEMENT ("Second Amendment") is
made  and  executed  as of this  28th  day of  September,  1998  by and  between
CORPORATE  OFFICE  PROPERTIES  TRUST  and  CORPORATE  OFFICE  PROPERTIES,   L.P.
(collectively, the "Buyer") and the Sellers listed on the signature page to this
Second Amendment and as defined in the Contribution Agreement (collectively, the
"Sellers" and each individually, a "Seller").

         A. Sellers and Buyer entered into a  Contribution  Agreement  dated May
14,  1988,  as amended on July 16,  1998 by a First  Amendment  to  Contribution
Agreement (the  "Contribution  Agreement"),  pursuant to which Sellers agreed to
contribute a property  known as Brandon and certain  interests in Entities which
own certain  real estate and a mortgage in Maryland to the Buyer in exchange for
cash,  the  assumption  of  certain  debt,  and Common  Shares  and  Convertible
Preferred  Shares.  Capitalized  terms  used,  but not  defined,  in this Second
Amendment  shall  have  the  meanings  given to such  terms in the  Contribution
Agreement.

         B. Sellers and Buyer desire to amend the Contribution  Agreement as set
forth in this Second Amendment.

         NOW, THEREFORE, in consideration of the agreements contained herein and
intending to be legally bound hereby, Sellers and Buyer agree as follows:

                  1.  Exhibit  "TIF   Agreement"  is  hereby  deleted  from  the
Contribution  Agreement,  and Exhibit "TIF Agreement" attached hereto and made a
part hereof,  is hereby attached to and made part of the Contribution  Agreement
as Exhibit "TIF Agreement".

                  2.  Buyer  hereby  elects  to  convert  all of  the  Satisfied
Indebtedness   to  Assumed   Indebtedness   pursuant  to  Section  1.83  of  the
Contribution  Agreement.  Sellers  and CREG  shall be  released  from all future
liability under such converted Assumed Indebtedness.

                  3. Pursuant to Section 11.1.4 of the  Contribution  Agreement,
Sellers  have  elected to transfer  certain  partnership  and limited  liability
company  interests  prior to  Closing  as shown in  Exhibit  "Interest  Changes"
attached  hereto and made a part  hereof.  Except as shown on Exhibit  "Interest
Changes",  there have been no changes in the  composition  of any Entity between
May 14, 1998 and the date hereof.  Sellers  represent and warrant that certified
copies of all documents  necessary to effectuate the transfers  shown on Exhibit
"Interest Changes" will be delivered to Buyer on or before the First Closing.

                  4. The  term  "Development  Management  Agreement"  is  hereby
deleted from Section 1.31 of the Contribution  Agreement,  and the term "Project
Consulting  and  Management  Agreement" is  substituted  in its place.  The term
"Development  Management  Agreement"  is hereby  deleted  wherever it appears in
Section 5.7 of the Contribution Agreement,  and the term "Project Consulting and
Management Agreement" is hereby substituted in its place. Exhibit "Development



<PAGE>


Management  Agreement" is hereby deleted from the  Contribution  Agreement,  and
Exhibit "Projects Consulting and Management  Agreement" attached hereto and made
a part hereof, is hereby attached to and made part of the Contribution Agreement
as Exhibit "Project Management and Consulting Agreement".

                  5. The first  sentence  of Section  6.2.1 of the  Contribution
Agreement is amended by changing  "December 31, 1998" to "March 31,  1999".  The
second  sentence  of Section  6.2.2 is revised by adding at the end  thereof the
following language:

                  ";  provided,  however,  that  notwithstanding  the foregoing,
                  Buyer and  Sellers  shall  consummate  the  Woodlands  Closing
                  simultaneously   with  the  closing  of  the  first  financing
                  transaction  by Buyer for all or any  portion of the  Projects
                  transferred  to Buyer at the  First  Closing.  In the event of
                  such a simultaneous  closing of a financing  transaction  with
                  the  Woodlands  Closing,  the  Woodlands  Gross Value shall be
                  $17,600,000,  and shall not be  reduced  pursuant  to  Section
                  3.2.5; and Sellers shall, from time to time,  reimburse Buyer,
                  within seven (7) days after  presentation  of a bill therefor,
                  for all  interest  payments  with  respect to financing on the
                  Woodlands  I Project  from the date of the  Woodlands  Closing
                  until October 21, 1998."

                  6. Exhibit "Option Projects" to the Contribution  Agreement is
hereby deleted from the Contribution  Agreement,  and Exhibit "Option  Projects"
attached  hereto and made a part hereof,  is hereby attached to and made part of
the Contribution  Agreement as Exhibit "Option Projects".  All references in the
Contribution  Agreement to the Option Project identified as "Annapolis Exchange"
are deleted.

                  7. Exhibit "Projects" to the Contribution  Agreement is hereby
amended by adding to the reference for One Constellation Centre the following:

                  "Unit 5, Constellation Centre Condominium
                    vacant land
                    30,495 sq. ft. tract"

and by changing the reference to Constellation Centre - Nations Bank Parcel from
"25,933 sq. ft. tract" to "47,701 sq. ft. tract".

                  8. The  address  for  notices  to Buyer is hereby  changed  as
follows:

                              Corporate Office Properties Trust
                              401 City Avenue, Suite 615
                              Bala Cynwyd, PA  19004-1126
                              Attention:       Clay W. Hamlin, III
                                           President and Chief Executive Officer

                                       2
<PAGE>


Copies of notices to Buyer shall still be sent as set forth in the  Contribution
Agreement.


         IN WITNESS WHEREOF,  and intending to be legally bound hereby,  Sellers
and Buyer have  executed  this Second  Amendment on the day and year first above
written.

                                   BUYER:

                                   CORPORATE OFFICE PROPERTIES, L.P.

                                   By:      Corporate Office Properties Trust,
                            its sole general partner


                                   By:               /s/ Clay W. Hamlin
                                                     Clay W. Hamlin, III
                                           President and Chief Executive Officer


                                   SELLERS:

                                   CONSTELLATION PROPERTIES, INC.,
                                   a Maryland corporation


                                   By:      /s/ Dan R. Skworonski
                                Dan R. Skowronski
                                    Secretary

                                   CPI NATIONAL BUSINESS PARK I, INC.,
                                   a Maryland corporation


                                   By:     /s/ Dan R. Skworonski
                                              Dan R. Skowronski
                                                  Secretary

                                   CPI NATIONAL BUSINESS PARK II, INC.,
                                   a Maryland corporation


                                   By:    /s/ Dan R. Skowronski
                                            Dan R. Skowronski
                                               Secretary

                       [SIGNATURES CONTINUED ON NEXT PAGE]


                                       3
<PAGE>

                                   CPI NATIONAL BUSINESS PARK IV, INC.,
                                   a Maryland corporation


                                   By:   /s/ Dan R. Skowronski
                                            Dan R. Skowronski
                                               Secretary

                                   CPO CONSTELLATION CENTRE, INC.,
                                   a Maryland corporation


                                   By:    /s/ Dan R. Skowronski
                                            Dan R. Skowronski
                                               Secretary

                                   CPO LAUREL TOWER, INC.,
                                   a Maryland corporation


                                   By:     /s/ Dan R. Skowronski
                                              Dan R. Skowronski
                                                  Secretary

                                   CPO THREE CENTRE PARK, INC.,
                                   a Maryland corporation

                                   By:    /s/ Dan R. Skowronski
                                            Dan R. Skowronski
                                                Secretary

                                   CPI BROWN'S WHARF, INC.,
                                   a Maryland corporation


                                   By:     /s/ Dan R. Skowronski
                                              Dan R. Skowronski
                                                  Secretary


                       [SIGNATURES CONTINUED ON NEXT PAGE]

                                       4
<PAGE>



                    CPI PARTNER, INC., a Maryland corporation


                                   By:     /s/ Dan R. Skowronski
                                             Dan R. Skowronski
                                                 Secretary

                   CPI TRED AVON, INC., a Maryland corporation


                                   By:      /s/ Dan R. Skowronski
                                              Dan R. Skowronski
                                                  Secretary

                  CPI GATESPRING, INC., a Maryland corporation


                                   By:      /s/ Dan R. Skowronski
                                Dan R. Skowronski
                                    Secretary

                                       5
<PAGE>


                            EXHIBIT "TIF AGREEMENT "

                            INDEMNIFICATION AGREEMENT
                          (National Business Park--TIF)

         THIS INDEMNIFICATION AGREEMENT ("Agreement") is made  this  28th day of
September, 1998 by CONSTELLATION PROPERTIES,  INC. ("CPI") in favor of CORPORATE
OFFICE  PROPERTIES  L.P.   ("COPLP");   CPI  being  sometimes   referred  to  as
"Indemnitor" and COPLP, and its successors and assigns, being sometimes referred
to as "Indemnitee."
                                   WITNESSETH
         WHEREAS,  CPI,  through  various related and affiliated  entities,  has
developed  and  continues  to develop the  "National  Business  Park",  which is
located in Annapolis Junction, Anne Arundel County, Maryland (the "Park");
         WHEREAS,   in  connection   with  the  development  of  the  Park,  CPI
determined,  in  conjunction  with the County  Council of Anne  Arundel  County,
Maryland,  that in  order  to  most  efficiently  and  effectively  develop  the
necessary  infrastructure and public  improvements in and around the vicinity of
the Park, that Anne Arundel County would (i) impose tax incremental financing on
certain properties located in the County, including, among others, the Park, and
(ii) create a Special  Tax  District  which  included  the Park  pursuant to the
authority  granted to the County  Council by Article 6, Title 4A, Section 4A-101
et seq. of the Anne Arundel County Code;
         WHEREAS,  the Special Tax District  pertaining  to the Park is commonly
referred to as the "NBP  Special Tax  District"  and was  approved by the County
Council of Anne Arundel County on March 4, 1998, in Bill No. 15-98;
         WHEREAS,  as of the date  hereof,  COPLP has (i)  acquired an ownership
interest in several of the NBP Properties described as Lot 3B (commonly referred
to as the  "Tower"  or "One  National  Business  Park"),  Lot 6AR (known as "131
National Business Park"),  Lot 6-BR (known as "133 National Business Park"), Lot
7A (known as "135 National Business Park") and Lot 7B (known as "141 National


<PAGE>



Business  Park")  and (ii) will  acquire  an  interest  in Lot 11 (known as "134
National  Business Park") pursuant to the terms of that certain Option Agreement
dated May 14, 1998 by and between NBP-III, LLC and COPLP;
         WHEREAS,  One National  Business Park, 131 National  Business Park, 133
National  Business  Park, 135 National  Business Park and 141 National  Business
Park and 134 National  Business Park are referred to collectively  herein as the
"COPLP Properties";
         WHEREAS, CPI does not anticipate that there will be any increase in the
taxes or  assessments  levied  on the  COPLP  Properties  as a result of the tax
incremental  financing or the creation of the NBP Tax  District,  as compared to
the taxes or assessments that would be levied on the COPLP Properties if the tax
incremental financing or the NBP Tax District did not exist;
         WHEREAS,  in consideration of COPLP acquiring an ownership  interest in
the COPLP Properties,  to the extent that the taxes and/or assessments levied on
the COPLP Properties as a result of the creation and continued  existence of the
tax incremental  financing and/or the NBP Tax District exceed those taxes and/or
assessments  which would be levied if the tax incremental  financing  and/or NBP
Tax District did not exist (the "Tax Differential"), CPI has agreed to indemnify
and hold COPLP harmless from and against any additional taxes and/or assessments
resulting from the Tax Differential  which are levied on the COPLP Properties in
which COPLP or any affiliates or subsidiary acquires an ownership interest.
         NOW THEREFORE, it is mutually agreed, as follows:
         1.       Incorporation  of  Recitals.  The  Recitals  shall  be  deemed
to be an  integral  part  of this Agreement.
         2.       Indemnification.
                  2.1 Indemnitor hereby indemnifies Indemnitee and undertakes to
hold it harmless from the Tax Differential and shall reimburse Indemnitee within
forty-five  (45)  days  after  receipt  from  Indemnitee  of  a  written  notice
identifying  the  amount  of the  Tax  Differential  and  reasonable  supporting
documentation ("Indemnitee's Request").
                  2.2  Indemnitor  shall  notify  Indemnitee  in writing  within
thirty (30) days after receipt of Indemnitee's  Request of any objections to the
Indemnitee's Request (the "Objection Notice"). If Indemnitor delivers an

                                       2
<PAGE>



Objection  Notice within the thirty (30) day period,  Indemnitor  shall have the
right to extend the  forty-five  (45) day period for payment  for an  additional
period of  forty-five  (45) days  (resulting in payment  being  required  within
ninety  (90)  days  after  the  date of  Indemnitee's  Request)  to  permit  the
Indemnitor to evaluate the cause for the Tax  Differential  with the appropriate
officials of Anne Arundel County.
                  2.3 If Indemnitor determines, in conjunction with Anne Arundel
County,  that the Tax  Differential  claimed by the  Indemnitor was not computed
accurately,  Indemnitor shall notify the Indemnitee in writing on or before that
day which is sixty  (60)  days  after the date of  Indemnitee's  Request  of the
accurate  amount  of the Tax  Differential,  if any,  together  with  reasonable
supporting  documentation  which is either  prepared by Anne  Arundel  County or
obtained from its records.
                  2.4 Any  claims  made by  Indemnitee  under  the terms of this
Agreement  shall be made  within  three (3) years after the date of that the Tax
Differential is assessed or levied.
         3. Term.  The term of this  Agreement  shall be from the date hereof to
that date which is twenty (20)  calendar  years after the date hereof  ("Term").
Indemnitee shall have no further rights to deliver an Indemnitee's Request after
the expiration of the Term.
         4. Binding Nature.  This Agreement and all duties and rights  hereunder
shall run with the land and shall be  binding  on  Indemnitor's  successors  and
assigns and shall inure to the benefit of Indemnitee's successors and assigns.
         5.       Miscellaneous.
                  (a) Notices.  Any notice required by the terms hereof shall be
given in writing at the address set forth below by any of the  following  means:
(a) personal service, (b) electronic communication, whether by facsimile, telex,
telegram or telecopy,  (c)  registered or certified  United State mail,  postage
prepaid,  return receipt requested,  or (d) by nationally  recognized  overnight
delivery service, as follows:
                    CPI:                      Constellation Properties, Inc.
                                              8815 Centre Park Drive, Suite 100
                                              Columbia, Maryland   21045
                                              Attn: President

                    With a copy to:           Constellation Properties, Inc.
                                              250 West Pratt Street, 24th Floor
                            Baltimore, Maryland 21201
                              Attn: General Counsel

                                       3
<PAGE>


                    COPLP:                    Corporate Office Properties, L.P.
                                              8815 Centre Park Drive, Suite 400
                                              Columbia, Maryland   21045
                              Attn: General Counsel

                    With a copy to:           Corporate Office Properties L.P.
                                              Corporate Office Properties Trust
                           401 City Avenue, Suite 615
                           Bala Cynwyd, PA 19004-1126
                         Attention: Clay W. Hamlin, III
                                                           President and Chief
                                                           Executive Officer

            Such  address(es)  may be changed  by either  party by notice to the
other in the manner provided  above.  Any notice sent (i) pursuant to subsection
(a) shall be deemed received upon personal service,  (ii) pursuant to subsection
(b) shall be deemed received upon dispatch by electronic  means,  (iii) pursuant
to subsection (c) shall be deemed  received  three (3) days following  depositin
the United  States mail,  and (iv)  pursuant to  subsection  (d) shall be deemed
received  one (1)  business  day after  delivery  to the  nationally  recognized
overnight delivery service.
                  (b)  Applicable  Law. The formation of this  Agreement and the
respective  rights and  obligations of the parties under this Agreement shall be
construed in accordance with the laws of the State of Maryland.
                  (c)   Captions.   The  captions  of  the   Agreement  are  for
convenience  purposes  only and  shall  have no effect  on its  construction  or
interpretation.
                  (d)    Counterparts.    This   Agreement   may   be   executed
simultaneously  in one or more  counterparts,  each of which  shall be deemed an
original but all of which together shall constitute one and the same instrument.
                  (e)  Entire  Agreement.This   Agreement,   together  with  any
exhibits  attached  hereto,  represents the entire  agreement  between Owner and
Manager and all prior agreements and negotiations have been merged herein.  This
Agreement may not be changed or terminated orally.


                                       4
<PAGE>



                  (f) Severability. Each provision of this Agreement is intended
to be severable.  If any term or provision of this Agreement shall be determined
by a court of  competent  jurisdiction  to be illegal or invalid  for any reason
whatsoever,  that  provision  shall be severed from this Agreement and shall not
affect the validity of the remainder of this Agreement.
                  (g)  Attorney's  Fees.  If any  action  at law or in equity is
necessary to enforce or interpret the terms of this  Agreement,  the  prevailing
party shall be entitled  to  reasonable  attorney's  fees,  costs and  necessary
disbursements in addition to any other relief to which such may be entitled.
         IN WITNESS  WHEREOF,  the parties have  executed  this  Agreement to be
effective on the day and year first set forth above.

ATTEST:                                    CONSTELLATION PROPERTIES, INC.



 _______________________________           By:    /s/ Dan R. Skowronski
                                                   Dan R. Skowronski, Secretary


ATTEST:                                    CORPORATE OFFICE PROPERTIES L.P.


                                           By: Corporate Office Properties Trust
                           , its sole general partner


_______________________________            By:   /s/ Clay W. Hamlin, III
                                                   Clay W. Hamlin, III
                                                 President and Chief Executive
                                                            Officer


                                       5
<PAGE>


STATE OF                    COUNTY                    OF                   ,

TO WIT:

         I HEREBY CERTIFY, that on this     day of               , 1998,
before  me, undersigned Notary Public of said State, personally appeared       ,
who acknowledged himself to be the                     of Constellation
Properties,  Inc.,  a Maryland  corporation,  known to me or  satisfactorily
proven to be the person whose name is subscribed  to the  within  instrument,
and  acknowledged  that he  executed  the  same for the  purposes  therein
contained as the duly authorized              of said corporation
by signing the name of the corporation himself as

         IN WITNESS  WHEREOF,  I have set my hand and Notarial Seal, the day and
year first above written.

                                           ------------------------------------
                                                        Notary Public

My commission expires:




STATE OF                 COUNTY                    OF                   ,

TO WIT:

    I HEREBY CERTIFY,  that on this __ day of__ , 1998,  before me,  undersigned
Notary Public of said State,  personally  appeared CLAY W. HAMLIN, III, known to
me or  satisfactorily  proven to be the person whose name is  subscribed  to the
within  instrument,  who  acknowledged  himself  to be the  President  and Chief
Executive  Officer of  Corporate  Office  Proerties  Trust,  general  partner of
Corporate Office Properties L.P., a limited partnership and acknowledged that he
executed the same for the  purposes  therein  contained  as the duly  authorized
President and Chief  Executive  Officer of said general  partner of said limited
partnership  by signing the name of the  corporation by himself as President and
Chief Executive Officer.

         IN WITNESS  WHEREOF,  I have set my hand and Notarial Seal, the day and
year first above written.

                                            -----------------------------------
                                                        Notary Public

                             My commission expires:
                                        6

<PAGE>


                             ATTORNEY CERTIFICATION

         THE UNDERSIGNED,  an attorney  admitted to practice before the Court of
Appeals of Maryland,  hereby certifies that the above instrument was prepared by
me or under my supervision.



                                           -----------------------------------
                                            John Harris Gurley, Attorney-at-Law


                                       7
<PAGE>


                           EXHIBIT "INTEREST CHANGES"


                                     Type of Interest     Original %   Closing %
                                     ----------------     ----------   ---------
PARTNERSHIPS

Brown's Wharf Limited Partnership

    Constellation Properties, Inc.         GP               0.4           0.4
                                           LP              39.6          98.6

    CPI Brown's Wharf, Inc.                GP               0.6           0.6
                                           LP              59.4           0.4

NBP-II Limited Partnership

    Constellation Properties, Inc.         GP              2.0           2.0
                                           LP             2.94          78.0

    CPI National Business Park
      II, Inc.                             GP              0.0           0.0
                                           LP            95.06          20.0

LIMITED LIABILITY COMPANIES

Tred Lightly Limited Liability Company

    Constellation Properties, Inc.       Member            0.0          75.0

    CPI Tred Avon, Inc.                  Member           75.0           0.0

    TA Associates                        Member           25.0          25.0
    Limited Partnership


                                       7
<PAGE>


              EXHIBIT "PROJECT CONSULTING AND MANAGEMENT AGREEMENT"


                   PROJECT CONSULTING AND MANAGEMENT AGREEMENT

         THIS PROJECT  CONSULTING  AND  MANAGEMENT  AGREEMENT  (hereinafter  the
"Agreement")  is made as of the  28th day of  September,  1998,  by and  between
CONSTELLATION  PROPERTIES,  INC.  (hereinafter  "Owner"),  and CORPORATE  OFFICE
MANAGEMENT, INC., a Maryland Corporation (hereinafter "Manager").

                              W I T N E S S E T H:

         WHEREAS,  Owner through its various  subsidiaries and affiliates is the
owner of a portfolio of properties  and projects (both vacant land and buildings
in  construction)   located  in  the  Central  Maryland  area  (hereinafter  the
"Properties"),  the exact  locations and  designations  of the Properties  being
known by the parties hereto;

         WHEREAS,  Owner is managing its ownership of the Properties,  including
the planning and development of the Properties for  residential,  commercial and
industrial uses; and

         WHEREAS,  Owner and Manager  acknowledge  and agree that the  following
projects are included,  among others, within the Properties and are currently in
various stages of  development  by the Owner through the specified  subsidiaries
and affiliates:  (i) NBP IV, LLC is the owner of an office building known as 135
National  Business  Parkway  which project is nearing  completion;  needing only
certain interior,  elevator and exterior landscaping work to be completed;  (ii)
Constellation  Gatespring,  LLC is the owner of an office building project known
as  Woodlands  One which  project is nearing  completion;  (iii)  Piney  Orchard
Village  Center,  LLC is the  owner of a  retail  strip  project  known as Piney
Orchard  Village  Center which  project is under  construction  with  completion
scheduled for completion December 31, 1998; and (iv) Constellation  Springfield,
LLC is the owner of 60% LLC interest in another  entity  (Fran-Spring  TSA, LLC)
which is the owner of a retail shopping center in Springfield,  Virginia,  which
project is under construction with completion  scheduled for December 31, 1998 (
the  foregoing  items (i) through  (iv)  collectively  referred to herein as the
"Under Development Projects").

         WHEREAS,  Owner desires to employ Manager to provide ongoing  planning,
management  and  consulting  services with respect to the  management of Owner's
Properties,  including  management of the completion of development of the Under
Development Projects;

         WHEREAS,  Owner  desires  to employ  Manager  as set forth  herein  and
Manager is willing to manage same in accordance with the terms set forth herein.


<PAGE>


         NOW,  THEREFORE,  in  consideration  of the sums of money to be paid by
Owner to Manager, and in further consideration of the mutual covenants contained
herein, the parties hereto agree as follows:

                  1.       Recitals.  Each party represents  to  the  other that
the recitals set forth above contain no material misrepresentation of fact.

                  2. Employment of Manager.  Owner hereby retains  Manager,  and
Manager  hereby  agrees,  to provide to Owner  consulting  services  and general
management  and  administration  services with respect to the  Properties and to
initiate,  and thereafter,  to diligently  coordinate,  supervise and pursue all
steps necessary to implement  development plans for the various  Properties upon
such schedules as are reasonably  approved from time to time by Owner,  upon the
terms and conditions, and for the term and compensation hereinafter set forth.

                  3. Term. The term of this Agreement,  and of the employment of
Manager by Owner pursuant hereto,  shall be for the period  commencing as of the
date  hereof  and  ending on the date that is the last day of the month  that is
eighteen (18) months after the date of this Agreement ("Term").

                  4.  Services.  Subject to the  direction and control of Owner,
the  consulting,  development,  management  and  administrative  services  to be
rendered by Manager shall,  when  appropriate,  include,  but not be limited to,
each of the following services:

                           (a) Preliminary site analysis and project planning.

                           (b) Coordinate and manage the process of securing
preliminary approval of the land use plans and the preliminary engineering
criteria.

                           (c) Assist Owner in retaining appropriate consultants
related to the various  Properties  including,  but not  limited  to,  landscape
architect,  civil  engineer,   architect,  traffic  consultant,  soil  engineer,
attorney,   accountant,   marketing  consultant,   appraiser  and  surveyor  and
thereafter,  act as  Owner's  representative's  contact  with  such  consultants
regarding the development of the Properties.

                           (d) Act as Owner's representative and liaison with
community and other civic groups in connection with the development of the
Properties.

                           (e)Assist in the preparation of cost line budgets and
cash flow projections for the development of the Properties.

                           (f) Prepare and monitor  compliance with  development
schedules approved by Owner.

                                       2
<PAGE>



                           (g) Coordinate the securing of all appropriate and
necessary governmental approvals relating to the development plans for the
Properties.

                           (h) Consult with respect to the management of the
Properties which are not in development at any one time.

                           (i) Consult with engineers, lenders and attorneys the
securing of all permits and the posting of all security required for the
development of the Properties.

                           (j) Consult with respect to the issuance of all
construction  bid documents,  provide  analysis of bids and  recommendations  on
awards  of  contracts,   and  assist  in  the  issuance  of  contracts  for  all
construction work.

                           (k) Assist in the coordination of construction
activities  relating to the Project by visiting the site during  critical phases
of construction and by meeting with County officials,  inspectors,  contractors,
subcontractors and construction supervisors.

                           (l) Coordinate land development documentation with
marketing  programs  including,  but not  limited  to,  the  preparation  of any
homeowner's  association documents,  cross-easements,  declarations of covenants
and restrictions and deeds to governmental  bodies for roads,  recreation spaces
and open spaces.

                           (m) Advise on the status of all construction/building
permits and the release of all security posted in connection with the
development of the Properties.

                           (n) Provide advice on the overall marketing and
publicity program for the Properties including advertising, signage, promotional
brochures and model homes parks.

                           (o) Meet regularly with designated representatives of
Owner and furnish  summary  reports on at least a monthly basis  reflecting  the
status of overall development.

         With regard to the above enumerated services to be performed by Manager
hereunder it is agreed that the parties will regularly  consult and mutually and
reasonably  agree  upon the  scope,  timing,  order of  importance  and  overall
direction of the services.

         Notwithstanding  anything  herein to the contrary,  with respect to the
Under Development Projects,  Manager shall provide all those management services
reasonably  required by Owner (or Owner's  subsidiary  or affiliate  which holds
title to each of the Under  Development  Projects) in  connection  with bringing
each of the  Under  Development  Projects  to  completion  as  evidenced  by the
obtaining  for  each  Under  Development  Project  of a  certificate  of use and
occupancy or similar governmental permit. The work of Manager shall generally be
described as the performance of all those managerial and oversight functions

                                       3
<PAGE>


reasonably  required so as to bring each Under  Development  Project to physical
completion on a timely basis and in line with budgeted costs.

                  5. Costs and Expenses. Owner shall pay, and Manager shall have
no  responsibility  whatsoever  for,  the  payment of any  independent  costs or
out-of-pocket  expenses  incurred in connection with the work to be performed by
it hereunder.  Manager shall be responsible  only for its own overhead  expenses
incurred in the  performance of its obligations  under this  Agreement.  Manager
shall not  authorize or incur outside costs in excess of $5,000 for any one item
or service without the prior written approval of Owner. Notwithstanding anything
herein  to the  contrary,  with  regard to the Under  Development  Projects,  in
performing its management  services  hereunder Manager shall use its good faith,
commercially reasonable efforts to consult with Owner to save costs and to bring
each Under  Development  Project to completion  at a cost within prior  approved
budgeted  sums.  Under  no  circumstances  shall  Manager  authorize  or  permit
additional costs above budget or changes to any Under  Development  Project that
would  increase  costs without same being  approved in advance and in writing by
the Owner of the particular Under Development Project.

                  6.       Owner's Responsibility.  Owner shall:

               (a) Reimburse Manager for all independent costs and out-of-pocket
          expenses  properly  incurred and  approved  (if  required) by Owner in
          accordance with the terms hereof.

               (b) Pay to Manager for its  services as  rendered  hereunder  the
          total  sum of  $2,000,000.  This  sum  shall be paid as  follows  on a
          monthly basis:

               (i) $250,000 per month from the date hereof  through the last day
          of the third (3rd) calendar month after the date hereof;

               (ii)  $150,000  per month from the first day of the fourth  (4th)
          calendar month after the date hereof through the last day of the sixth
          (6th) calendar month after the date hereof;

               (iii)  $100,000 per month from the first day of the seventh (7th)
          calendar month after the date hereof through the last day of the tenth
          (10th) calendar month after the date hereof;

               (iv) $50,000 per month from the first day of the eleventh  (11th)
          calendar  month  after  the date  hereof  through  the last day of the
          eighteenth (18th) calendar month after the date hereof.

               (c) Indemnify  and hold Manager and all of its officers,  agents,
          servants and employees, harmless from and against any claims, actions,
          damages,  losses and expenses (including  attorney's fees) of any kind
          whatsoever arising out of or in connection with the work and services

                                       4

<PAGE>



          performed by Manager hereunder, except Owner shall not be liable under
          this  clause  if said  liability  shall  arise by  reason of the gross
          negligence or intentional  misconduct of Manager. Owner agrees that it
          will have  Manager  added as a named  insured on the public  liability
          policies acquired by the various owners of the Properties.

               (d) Cooperate with Manager in expediting  the  performance of its
          work  hereunder.  Owner shall  cooperate with Manager by (i) providing
          information,  (ii) providing funds required  pursuant to invoices from
          and contract  with  providers  of services and  suppliers of materials
          with respect to the various  Properties,  (iii) rendering decisions on
          matters  affecting  the  development  of the various  Properties,  all
          within  the  timeframes  and in the  form  reasonably  recommended  by
          Manager.

                  7.  Limitation  on Manager's  Responsibility.  It is expressly
understood and agreed between the parties hereto, that notwithstanding  anything
to the contrary in this  Agreement,  (i) Manager does not warrant,  or guarantee
the performance of any  professional  or contractor  employed in connection with
the Properties or warrant or guarantee the performance of under any construction
contracts  relating to the  Properties.  Moreover  the  consulting  development,
management  and  administrative  services  rendered  by Manager  hereunder  will
involve  recommendations as to how the various Properties might be developed and
estimates made by Manager as part of its development  management  services,  and
the assumptions upon which they are based,  represent  Manager's  judgment based
upon   available   information   as  of  the  date  of   preparation.   No  such
recommendation,  estimate or  assumption  is intended to  constitute a warranty,
guarantee  or promise by Manager that the stated  objectives  can be achieved in
the  manner  described.  Manager  shall not be liable to Owner if any of Owner's
objectives with respect to the Properties are not achieved either in whole or in
part or in a timely manner or otherwise.

                  8. Default.  If either party to this Agreement defaults in the
performance of its obligations under this Agreement after notice and opportunity
to cure set forth  below in Section 8, the  non-defaulting  party shall have all
rights  and  remedies  available  to it at law or in equity on  account  of such
default,  provided,  however,  that  Owner  shall not have the right to seek the
remedy of termination of this Agreement  unless and until Manager has been given
the  notice  and  opportunity  to cure set forth  below in this  Section  8, and
thereafter,   a  court  of   competent   jurisdiction   has  rendered  a  final,
non-appealable decision holding that the Manager has committed a material breach
of  this  Agreement.  Anything  contained  in  this  Agreement  to the  contrary
notwithstanding,  any act or omission  which would  otherwise be a default under
this Agreement by either party shall not be a default unless the  non-defaulting
party shall have given the defaulting party notice of such alleged default,  and
the  defaulting  party shall have  failed to cure such  alleged  default  within
thirty  (30) days  after such  notice,  or if the  alleged  default is one which
cannot with due diligence be cured within thirty (30) days, the defaulting party
shall have failed to commence  curing such  default  within such thirty (30) day
period.

                  9.  Notices.  All notices  required  or  provided  for in this
Agreement, if hand delivered shall be deemed to have been given and received on

                                       5

<PAGE>



the date hand delivered to the party  receiving same. If the United States mails
are used,  notices shall be sent  certified or registered  mail,  return receipt
requested,  postage prepaid, and shall be deemed to have been given and received
on the second (2nd)  business day from the date  deposited in the United  States
mails addressed as follows:

                                  If to Owner:

                         Constellation Properties, Inc.
                         Attention: Mr. Steven S. Koren
                         8815 Centre Park Drive - Suite 100
                         Columbia, MD 21045

                                    and

                          Dan R. Skowronski, Esquire
                          Constellation Holdings, Inc.
                          250 W. Pratt Street
                          23rd Floor
                          Baltimore, MD  21201

                                 If to Manager:

                           Corporate Office Management, Inc.
                           Attention:  Mr. Dan R. Skowronski
                           8815 Centre Park Drive - Suite 400
                           Columbia, MD   21045

                                       and

                            Mr. Clay W. Hamlin, III
                            Corporate Office Properties Trust
                            401 City Avenue. Suite 615
                            Bala Cynwyd, PA 19004

         Each  party  shall have the right to  designate  a  different  address,
provided the party's new address is  contained in a written  notice to the other
party.

                  10.      Miscellaneous.

               (a) This Agreement contains the final  understanding of the terms
          and provisions  between the parties and supersedes any prior agreement
          among the parties.

               (b) This  Agreement  shall be  interpreted  under the laws of the
          State of Maryland.

                                       6

<PAGE>

               (c)  If  any   provision  of  this   Agreement  is  found  to  be
          unenforceable  or void,  the remaining  provisions  of this  Agreement
          shall be enforceable between the parties.

               (d) This  Agreement  may not be assigned by either  party  hereto
          without  the  consent  of  the  other   party,   which  shall  not  be
          unreasonably withheld or delayed,  except that either party may assign
          to a subsidiary or affiliate of it without the prior  written  consent
          of the other party.

               (e) Nothing in the provisions of this  Agreement  shall be deemed
          in any way to create  between the parties hereto any  relationship  of
          partnership,  joint  venture or  association,  and the parties  hereto
          hereby disclaim the existence thereof.

               (f) Each party hereto warrants and represents that the person who
          has signed this Agreement on its behalf is duly authorized to so sign,
          and this Agreement is the legal,  valid and binding  agreement of such
          party, enforceable against such party, in accordance with its terms.

               (g)  Manager  agrees  that  it  will  not  disclose  confidential
          information  furnished  to  it  by  Owner  as  a  consequence  of  its
          employment under this Agreement.

         IN WITNESS WHEREOF,  the parties hereto sign and seal this Agreement on
the day and year first above written.

WITNESS                                     CONSTELLATION PROPERTIES, INC.


________________________________    By:     _____________________________(SEAL)


                                             CORPORATE OFFICE MANAGEMENT, INC.


________________________________    By:     _____________________________(SEAL)


                                       7

<PAGE>


                            EXHIBIT "OPTION PROJECTS"

         All documents listed below are attached.

         1.       National Business Park
                           5 Year Option and Right of First Refusal

         2.       Brown's Wharf adjacent land - Right of First Refusal

         3.       Constellation Centre Unit 2 and 7 - Right of First Refusal









                  SERVICE COMPANY ASSET CONTRIBUTION AGREEMENT


         SERVICE COMPANY ASSET  CONTRIBUTION  AGREEMENT,  entered into as of the
14th day of May, 1998, by and among Constellation Real Estate,  Inc., a Maryland
corporation  ("Seller"),  KMS Oldco,  Inc. a Maryland  corporation  ("KMS")  and
Constellation Real Estate Group, Inc. a Maryland corporation ("CREG"),  (KMS and
CREG are collectively  referred to herein as the "Shareholders"),  and Corporate
Office Properties,  L.P., a Delaware limited  partnership  ("COP") and Corporate
Office Properties  Trust, a Maryland real estate investment trust ("COPT").  COP
and COPT are collectively referred to herein as "Buyer."


                              W I T N E S S E T H:

          Seller is engaged  directly,  and indirectly  through its  controlling
ownership interest in Constellation  Realty Management,  LLC, a Maryland limited
liability   company   ("CRM")  in  the  business  of  managing  real   property.
Shareholders  are the owners of all the issued and outstanding  capital stock of
Seller.

         COPT is the sole  General  Partner  of COP.  COP and COPT have this day
entered into a certain Contribution Agreement and certain Development Agreements
which  provide,  inter  alia,  for the  transfer  to Buyer of certain  ownership
interests in entities  which are Affiliates of Seller and the  Shareholders  and
which own real property,  some of which real property has been managed by Seller
or CRM.

         Seller  wishes to sell and Buyer wishes to buy certain  assets owned by
Seller,  including all of Seller's interest as a member in CRM, and Buyer wishes
to assume certain of Seller's liabilities.

         In consideration of the mutual agreements,  covenants,  representations
and warranties  contained herein, and each intending to be legally bound hereby,
the parties hereto agree as follows:

ARTICLE 1.        DEFINITIONS.

         As used in this Agreement, the following terms shall have the following
meanings:


"Affiliate" as to a Person shall mean a Person that  controls,  is controlled by
or under common control with such Person.

"Accredited  Investor"  shall  have  the  meaning  set  forth  in  Regulation  D
promulgated under the Securities Act of 1933, as amended.


<PAGE>


"Agreement" means this Service Company Asset Contribution Agreement.

"Assets" has the meaning set forth in Section 2.1 (a) of the Agreement.

"Assumed  Liabilities"  has the  meaning  set  forth in  Section  2.5 (b) of the
Agreement.

"Authorizations"  has the meaning set forth in Section 8.3 of the Agreement.

"Balance Sheet Date" means April 30, 1998.

"Business"  means the operations and activities of Seller insofar as they relate
to the real properties which are owned by the entities whose interests are being
transferred to Buyer pursuant to the terms of the Contribution Agreement and the
Development Agreements.

"Buyer" means COP and COPT together.

"Closing"means  the closing of the  purchase  and sale of the Assets and the CRM
Interest pursuant to the terms of this Agreement.

"Closing Date" means the date on which the Closing shall occur.

"Code" means the Internal Revenue Code of 1986, as amended.

"Contracts"  has the meaning set forth in Section 2.1 (a) (iii)of the Agreement.

"Contribution  Agreement" means that Contribution  Agreement dated as of May __,
1998 by and between Buyer and the Persons identified therein as "Sellers".

"COP" means Corporate Office Properties, L.P.

"COPT" means Corporate Office Properties Trust.

"CREG" means Constellation Real Estate Group, Inc.

"CRM"  means Constellation Realty Management, LLC.

"CRM Balance Sheet" means the balance sheet of CRM as of April 30, 1998 included
on Schedule 4.8 to the Agreement.

"CRM  Financial  Statement"  has the  meaning  set forth in  Section  4.8 of the
Agreement.

"CRM Interest" means the seventy five percent (75%)  ownership  interest in CRM,
comprising all the issued and outstanding  Class A Units of CRM, owned by Seller
as a member of CRM.


                                       2
<PAGE>


"CRM Operating  Agreement"  means that Operating  Agreement  dated April 17,1996
between Seller and KLNB, LLC, attached hereto as Exhibit "A".

 "Deficiencies"  has the meaning set forth in Section 9.2 of the Agreement.

"Development  Agreements"  means those two  Development  Properties  Acquisition
Agreements  each dated as of May __, 1998 by and  between  Buyer and the Persons
identified therein as "Sellers".

"Employee  Benefit Plan" means employee benefit plans as defined in Section 3(3)
of ERISA.

"ERISA" means the Employee Retirement Income Security Act of 1974, as amended.

"Excluded Assets" has the meaning set forth in Section 2.1 (c) of the Agreement.

"GAAP" means generally accepted accounting principles, consistently applied.

"Informational  Materials"  shall have the meaning set forth in Section  4.30 of
the Agreement.

"KMS" means KMS Oldco, Inc.

"Law" means any law, including,  without limitation, any (i) principle of common
law, (ii) federal, state or local statute,  ordinance, rule or regulation,  (iv)
federal, state or local permit, license or certificate, or (iv) judgment, order,
decree,  award  or other  decision  or  requirement  of any  arbitrator,  court,
government or governmental agency or instrumentality (domestic or foreign).

"Person"  means  an  individual,  corporation,  partnership,  limited  liability
company, joint venture, organization, trust or other entity.

"Purchase Price" has the meaning set forth in Section 2.2 of the Agreement.

"SEC  Reports"  means  the  following  documents  filed to date by COPT with the
Securities and Exchange  Commission  pursuant to either the Securities  Exchange
Act of1934, as amended or the Securities Act of 1933, as amended:  Annual report
on Form 10- K for the year  ended  December  31,  1997;  Proxy  Statement  dated
February  11, 1998;  Prospectus  dated April 22, 1998  included in  registration
statement number 333-47465 filed pursuant to Rule 424(b);  and, Quarterly Report
on Form 10_Q for the three months ended March 31, 1998.

"Seller" means Constellation Real Estate, Inc.

"Shares" has the meaning set forth in Section 2.2 of the Agreement.

"Shareholders"  means,  collectively,  KMS and CREG, and "Shareholder" means any
one of the Shareholders.
                                       3

<PAGE>


"Taxes" means all Federal,  state,  local and foreign income,  property,  sales,
excise and other taxes or governmental charges of any nature whatsoever.

"Transaction  Documents"  has  the  meaning  set  forth  in  Section  4.2 of the
Agreement.



 ARTICLE 2.     TERMS OF ASSET PURCHASE; CLOSING.

         2.1      Sale and Purchase of Assets and CRM Interest.

                  (a) In reliance on the representations,  warranties, covenants
and agreements herein,  and subject to the terms and conditions  hereof,  Seller
shall sell, convey,  transfer and assign to Buyer, and Buyer shall purchase from
Seller, all of Seller's right, title and interest in and to substantially all of
the  tangible  and  certain  intangible  assets  owned or used by  Seller in the
Business as of the Closing Date (the "Assets"). It is understood and agreed that
all or a portion  of the  Assets may be  contributed  to,  and owned by,  single
member limited liability  companies in which Seller is the sole member, in which
case Seller shall sell and Buyer shall  purchase (or cause to be purchased)  all
of the interests of such entities. The Assets include,  without limitation,  the
following:

                    (i) all trade  fixtures,  fixed and movable  equipment,  and
               office equipment (including,  without limitation,  all repair and
               replacement  parts),  furniture,  all useable inventory of office
               supplies,  and all other items of tangible personal property used
               or employed in the conduct and  operation  of its  business as of
               the date of Closing;

                    (ii) all files  and  other  documents  and  records  and all
               books,  ledgers,  files  and  business  records  related  to  the
               Business;

                    (iii)  all  rights   existing   under   management   service
               agreements,  equipment leases,  contracts,  real property leases,
               supply  agreements,  purchase orders,  and all other  agreements,
               commitments and understandings,  to the extent the same relate to
               the Business and are assignable (collectively, the "Contracts");

                    (iv)  all  telephone   numbers  of  Seller  related  to  the
               Business;

                    (v)   all   permits,   licenses,   registrations,   filings,
               authorizations  and approvals (and pending  applications  for any
               thereof)  to the extent the same relate to the  Business  and are
               assignable by Seller to Buyer;

                    (vi) all prepaid items,  utility and other deposits  related
               to the Business and to which Seller is entitled,  supplier  lists
               related  to  the  Business,  and to the  extent  assignable,  all
               present  and future  causes of action and  claims  against  third
               parties related to the Business;


                                       4
<PAGE>


                    (vii) all rights to operate as a going concern,  to hire any
               past or present  employees,  and to do business  with all present
               customers and suppliers,  and all right and title to and interest
               in all goodwill of its business;

                    (viii)  all  computer  equipment,  databases,  software  and
               software  licenses  related to the Business (it being  understood
               and agreed that all such  equipment  and  information,  both hard
               copy and  computer-based,  which is not  related to the  Business
               shall not be part of the Assets); and

                    (ix) an  amount  of cash  which  shall  be no less  than the
               aggregate  amount of all  accrued but unpaid  payroll,  incentive
               pay,  vacation and associated  payroll taxes and benefit payments
               which Seller is required to pay for the current payroll period in
               which the Closing occurs (and any other unpaid amounts from prior
               periods)  but  only to the  extent  such  amounts  relate  to the
               employees  of  Seller  that  will  be  employed  by  Buyer  or an
               Affiliate of Buyer immediately after Closing.

                  (b) In reliance on the representations,  warranties, covenants
and agreements herein,  and subject to the terms and conditions  hereof,  Seller
shall sell, convey,  transfer and assign to Buyer, and Buyer shall purchase from
Seller, all of Seller's right, title and interest in and to the CRM Interest.

                  (c)  The  following  are  not  included  in  the  Assets  (the
"Excluded Assets"):

                    (i) all right,  title and  interest in and to Seller's  name
               and the service marks,  trade names,  trademarks and  copyrights,
               including all registrations and variances thereof,  logos used in
               connection  therewith,  the  right to sue for past  infringements
               thereof, and all goodwill associated with such marks and rights;

                    (ii) intercompany and other accounts receivable of Seller;

                    (iii)  trade  fixtures,  fixed and  movable  equipment,  and
               office equipment  (including,  without  limitation,  a reasonable
               amount of repair and replacement parts),  furniture, a reasonable
               amount of useable  inventory  of office  supplies,  and all other
               items of  tangible  personal  property  used or  employed  in the
               conduct and  operation  of its business as of the date of Closing
               by  those  employees  who  will  not be  employed  by Buyer or an
               Affiliate of Buyer immediately after Closing; and,

                    (iv) other items of personal  property set forth on Schedule
               2.1(c).

         2.2 Purchase Price and Payment. As consideration for the Assets and the
CRM Interest,  COPT shall  deliver to Seller the  aggregate  number of shares of
COPT Common Shares and COPT  Convertible  Preferred  Shares  (collectively,  the
"Shares") set forth on Schedule 2.2. (the "Purchase  Price").  It is agreed that
the value of the Purchase  Price is Two Million Five  Hundred  Thousand  Dollars
($2,500,000). The Purchase Price shall be allocated among the Assets and the CRM
Interest in the manner required by Section 1060 of the Code, and as set forth on
Schedule  2.2 hereto.  Seller and Buyer  hereby  agree to timely  file  Internal
Revenue Service Form 8594 and any other required Federal or State tax form with

                                       5
<PAGE>


respect to such allocation. No party hereto shall take, for income tax purposes,
any position inconsistent with such allocation.

         2.3 Expenses.  Seller,  the  Shareholders,  COP and COPT will each bear
their  respective  legal,  accounting and other expenses  incurred in connection
with the investigation, negotiation, preparation, review, execution, performance
and  enforcement  of this  Agreement,  and in connection  with the  transactions
contemplated hereby.

         2.4  Closing.  The  closing of the  transactions  contemplated  by this
Agreement (the "Closing") shall be held immediately  following,  and at the same
place  as the  closing  of the  transactions  contemplated  by the  Contribution
Agreement,  or at such other time and place as may be  mutually  agreed  upon by
Buyer and Seller.

         2.5   Assumption of Liabilities.

                  (a) Buyer  assumes  no  liabilities  of, or related  to,  CRM.
Except as expressly set forth in Section  2.5(b),  neither the execution of this
Agreement nor the  consummation of the  transactions  contemplated  herein shall
obligate  Buyer to pay any fixed or  contingent,  known or  unknown,  secured or
unsecured  obligation,  debt or liability of Seller or any Shareholder,  whether
arising  before or after the  Closing,  it being the  express  intention  of the
parties that Seller and the Shareholders shall be responsible for the payment of
all their  respective  obligations,  debts and liabilities,  including,  but not
limited to, indebtedness to banks and other financial institutions, indebtedness
to current and former employees,  officers, directors or shareholders of Seller,
and, liability for payment of any and all accrued and unpaid salaries and wages,
sick  pay,  vacation  pay,  time off or pay in lieu  thereof,  and any  employee
benefit due any employee.

                  (b) Notwithstanding the foregoing,  Buyer agrees to assume the
following obligations of Seller, and no others (the "Assumed Liabilities"):

                    (i)  obligations  of Seller under the Contracts set forth on
               Schedule 2.5(b) hereto,  but only to the extent that  performance
               of such obligations is to occur after Closing, or payment of sums
               due  thereunder  are in  consideration  for  products or services
               rendered to Buyer after the Closing Date;

                    (ii)  accounts  payable  then  current  and as  agreed to in
               writing by Buyer and Seller at or prior to Closing; and

                    (iii) accrued  payroll for the employees of Seller that will
               be employed by Buyer or an Affiliate of Buyer  immediately  after
               the  Closing,  and  associated  payroll  taxes  for the  Seller's
               current  payroll  period in which the  Closing  Date  occurs,  as
               agreed to in writing by Buyer and Seller at or prior to Closing.


                                       6
<PAGE>


 ARTICLE 3.            COVENANTS OF SELLER AND THE SHAREHOLDERS.

         Seller and the Shareholders jointly and severally covenant and agree to
and with Buyer as follows:

         3.1 Activities  Pending Closing.  Except as expressly  provided herein,
between the date hereof and Closing, unless Seller shall have received the prior
written  consent  of Buyer to the  contrary,  Seller  shall,  and Seller and the
Shareholders  shall  cause  each of  Seller  and CRM to use  their  commercially
reasonable best efforts to:

                  (i)  maintain  its  existence,  pay and  discharge  all debts,
liabilities  and  obligations  as they  become due,  and  operate  solely in the
ordinary  course of business in a manner  consistent  with past practice and the
provisions of this Agreement and in compliance in all material respects with all
applicable  Law and all  contracts  and  agreements  to which Seller or CRM is a
party or by which its assets are bound;

                  (ii) maintain its  facilities  and assets in the same state of
repair, order and condition as they were on the date hereof, reasonable wear and
tear excepted;

                  (iii)  maintain its books and records in accordance  with past
practice,  and use maintain in full force and effect all insurance  policies and
binders;

                  (iv) preserve intact its present organization and maintain its
relations and goodwill with  suppliers,  customers,  employees and others having
relationships with it;

                  (v)  promptly  advise  Buyer  in  writing  of  the  threat  or
commencement  against  Seller  or CRM  of  any  dispute,  claim,  action,  suit,
proceeding,  arbitration or investigation that could materially adversely affect
Seller or CRM,  or the assets of any  Shareholder,  or that  challenges,  or may
affect the validity of, this Agreement or any other Transaction  Document or any
action  taken or to be taken in  connection  with  this  Agreement  or any other
Transaction  Document  or the  ability  of any party  hereto to  consummate  the
transactions contemplated herein or therein; and

                  (vi)  promptly  advise  Buyer in  writing  of any event or the
existence of any fact which makes untrue, or will make untrue as of the Closing,
any  representation  or warranty of Seller or the Shareholders set forth in this
Agreement or in any Transaction Document.

         3.2 Negative  Covenants.  Except as expressly provided herein,  between
the date hereof and the  Closing,  without the prior  written  consent of Buyer,
Seller shall not, and Seller and the Shareholders shall cause each of Seller and
CRM not to:

                  (i) take any action  (regardless  of whether such action might
otherwise be permitted  hereunder),  or (through  inaction)  permit to occur any
event,   that  would,  or  could  reasonably  be  expected  to,  result  in  any
representation  of Seller or a  Shareholder  contained in this  Agreement  being
untrue in any material respect or the breach or  nonfulfillment of any warranty,
covenant or other obligation of Seller or a Shareholder in this Agreement;


                                       7
<PAGE>



                  (ii) amend its  Articles  of  Incorporation  or Bylaws (in the
case of Seller) or the CRM Operating Agreement (in the case of CRM) or any other
instrument regulating its conduct, including but not limited to agreements among
its owners;

                  (iii)  fail to pay or  discharge  when  due any  liability  or
obligation of Seller related to the Business or CRM;

                  (iv)  enter  into or renew,  extend,  amend or  terminate  any
agreement, commitment or transaction, which entry, renewal, extension, amendment
or  termination is not in the ordinary  course of business and  consistent  with
past  practice,  or  which is  material  to  Seller's  operations  or  financial
condition or CRM's operations or financial condition;

                  (v)      settle or  compromise   any   material  pending   or
threatened  litigation  or  proceeding related to the Business or to CRM;

                  (vi)  other  than  transactions  in  the  ordinary  course  of
business  consistent  with prior practice,  sell,  lease,  license,  encumber or
otherwise  dispose of, or agree to sell, lease,  license,  encumber or otherwise
dispose of, any assets that are material,  individually or in the aggregate,  to
it;

                  (vii)  except in the  ordinary  course of  business,  incur or
guaranty any indebtedness or make any loan;

                  (viii)   acquire any other business or interest therein;

                  (ix)  create,  enter  into,  adopt,  amend  (except  as may be
required by Law) or terminate any employee  benefit plan or any  compensatory or
benefit agreement,  arrangement, plan or policy with respect to any employee or,
except for normal  increases in the ordinary course of business  consistent with
past practice  that, in the aggregate,  do not result in a material  increase in
benefits or  compensation  expense,  increase in any manner the  compensation or
fringe benefits of any employee or consultant or pay any benefit not required by
any plan and  arrangement  as in effect as of the date  hereof or enter into any
contract, agreement, commitment or arrangement to do any of the foregoing; or

                  (x)      agree to do any of the foregoing.

         3.3 Access to Information.  Prior to the Closing,  Seller shall, during
ordinary  business hours and at mutually  convenient  times,  give Buyer and its
authorized  representatives reasonable access to all of its and CRM's personnel,
books, records, offices and other facilities and properties, and permit Buyer to
make such inspections thereof as Buyer may reasonably request, and cause its and
CRM's officers and advisors to furnish Buyer with such financial,  operating and
other  information  regarding  the  Business  and CRM as  Buyer  may  reasonably
request.

         3.4 Confidentiality. Seller and the Shareholders will keep confidential
and use their best efforts to cause their  affiliates and instruct its and their
respective  officers,  managers,  directors,  employees  and  advisors  to  keep
confidential all nonpublic information relating to the transactions


                                       8
<PAGE>


contemplated  hereby,  except as required by law or  administrative  process and
except for  information  which becomes public other than as a result of a breach
of this Section 3.4.

         3.5 Other Transactions.  Prior to the Closing neither Seller nor any of
the Shareholders shall, nor shall they permit any of their Affiliates, officers,
directors,  advisors  or  other  representatives  to,  directly  or  indirectly,
encourage, solicit, initiate or participate in discussions or negotiations with,
or provide any information or assistance to, any Person other than Buyer and its
representatives  concerning any merger,  sale of  securities,  sale of assets or
similar  transactions  involving the Seller or CRM In the event Seller or any of
the  Shareholders   receive  an  inquiry  or  proposal   relating  to  any  such
transaction, it or he will promptly notify Buyer thereof.

         3.6 Supplemental Disclosure. Seller and the Shareholders shall promptly
supplement  or amend each  Schedule  hereto with respect to any material  matter
hereafter  arising or discovered which, if existing or known at the date of this
Agreement,  would  have  been  required  to be set  forth or  described  in such
Schedule;  provided,  however, that any such supplemental or amended disclosures
shall  not be deemed to have  been  disclosed  as of the date of this  Agreement
unless so agreed to in writing by Buyer.

         3.7 Employees and Contractors.  Seller and the  Shareholders  shall use
their best efforts to assist Buyer in retaining the services of those  employees
of Seller and independent  contractors  with Seller that are identified by Buyer
for such purpose.

 ARTICLE 4.           REPRESENTATIONS AND WARRANTIES OF SELLER AND THE
                      SHAREHOLDERS.

         Seller and each of the Shareholders jointly and severally represent and
warrant to Buyer as follows:

         4.1 Status.  Seller is a corporation  duly organized,  validly existing
and in good  standing  under  the  laws of the  State of  Maryland,  and has all
requisite  corporate  power and authority to conduct its business as it has been
and is now  conducted,  to own and lease the  assets it owns and  leases  and to
perform its obligations pursuant to each agreement and instrument by which it is
bound. CRM is a limited liability  company duly organized,  validly existing and
in good standing under the laws of the State of Maryland,  and has all requisite
power and authority to conduct its business as it has been and is now conducted,
to own and lease the assets it owns and leases  and to perform  its  obligations
pursuant to each agreement and  instrument by which it is bound.  Neither Seller
nor CRM is required to be qualified to do business as a foreign  corporation  or
company in any jurisdiction  except as follows:  CRM is qualified to do business
in Virginia,  Delaware, New Jersey, West Virginia,  North Carolina, the District
of  Columbia  and  Pennsylvania;  and,  Seller is  qualified  to do  business in
Maryland and the District of Columbia.

         4.2 Power and  Authority.  Seller and each  Shareholder  has full legal
right,  power and  authority  to enter into and perform its and his  obligations
under this Agreement and under the other agreements and documents required to be
delivered by it hereunder prior to or at the Closing,  if any (the  "Transaction
Documents"). The execution, delivery and performance by Seller of this Agreement

                                       9

<PAGE>



and the other  Transaction  Documents have been duly authorized by all necessary
corporate  action.  This  Agreement  has been  duly  and  validly  executed  and
delivered by the Seller and by each Shareholder and constitutes the legal, valid
and binding  obligation  of each of them,  enforceable  against  each of them in
accordance with its terms.  When executed and delivered as contemplated  herein,
each of the Transaction  Documents shall constitute the legal, valid and binding
obligation  of  Seller  and each  Shareholder,  as the case may be,  enforceable
against each of them in accordance  with its terms,  subject to  bankruptcy  and
insolvency laws, and to equitable principles which may be imposed by courts.

         4.3 No  Conflicts.  The  execution,  delivery and  performance  of this
Agreement  and the  other  Transaction  Documents  do not and will not  (with or
without the  passage of time or the giving of  notice):  (i) violate or conflict
with Seller's Articles of Incorporation or Bylaws,  the CRM Operating  Agreement
or any Law binding upon Seller or CRM; (ii) violate or conflict with,  result in
a breach  of, or  constitute  a default or  otherwise  cause any loss of benefit
under, any agreement or other obligation to which CRM, Seller or any Shareholder
is a party or by which any of them (or the  assets of any of them) is bound,  or
give to any other party any rights  (including,  without  limitation,  rights of
termination,  foreclosure, cancellation or acceleration) in, or with respect to,
Seller,  the CRM Interest or any of the Assets; or (iii) result in, require,  or
permit the creation or imposition of, any restriction,  mortgage, deed of trust,
pledge,  lien, security interest or other charge,  claim or encumbrance upon, or
with respect to, Seller, the CRM Interest or any of the Assets.

         4.4  Shareholders.  The  Shareholders are the registered and beneficial
owners of one hundred percent (100%) of the issued and outstanding capital stock
of the  Seller  free and  clear of any  claims,  liens,  encumbrances,  security
interests,  options,  charges or restrictions whatever. No shares of the capital
stock of the Seller are subject to any voting trust agreement or other contract,
agreement,  arrangement,   commitment  or  understanding,   including  any  such
agreement,  arrangement,  commitment or  understanding  restricting or otherwise
relating to the voting,  dividend  rights or  disposition  of the capital stock.
There are no outstanding options, warrants, rights, puts, calls, commitments, or
other  contracts,  arrangements  (including  "phantom" stock  arrangements),  or
understandings  with respect to its capital  stock issued by or binding upon the
Seller. There are no obligations or agreements,  written or otherwise, requiring
or  otherwise  providing  for the  Seller  to (x)  make  any  dividend  or other
distribution,  direct or  indirect,  on or account of any shares of any class of
stock, now and hereafter outstanding, of the Seller or pursuant to any "phantom"
stock  arrangement;  or (y) make any redemption,  purchase or other acquisition,
direct or  indirect,  of any  shares of any class of stock of the  Seller now or
hereafter  outstanding  or of any  warrants or rights to purchase any such stock
(including,  without limitation,  the repurchase of any such stock or warrant or
any refund of the purchase price thereof in connection  with the exercise by the
holder  thereof of any right of  rescission  or similar  remedies  with  respect
thereto).

         4.5 Investments,  Subsidiaries and Controlled  Entities.  Except as set
forth on Schedule  4.5,  neither  Seller nor CRM  directly or  indirectly  owns,
controls or has any  investment  or  membership  or other  interest in any other
Person.


                                       10
<PAGE>



         4.6 Compliance with Law and Other Requirements.  Each of Seller and CRM
is, and at all times since its inception has been, in compliance in all material
respects  with all  applicable  Law, and has not  received any notice,  order or
other  communication  from any  governmental  agency or  instrumentality  of any
alleged,  actual, or potential violation of, or failure to comply with, any Law.
All federal,  foreign,  state, local and other governmental consents,  licenses,
permits,  franchises,  grants,  approvals  and  authorizations  required for the
activities of Seller and CRM as currently conducted are in full force and effect
without any  default or  violation  thereunder  by Seller or CRM or by any other
party thereto,  except where such default or violation would not have a material
adverse effect on the activities,  financial  condition or results of operations
of Seller or CRM.

         4.7  Employee  and Labor  Relations.  Schedule  4.7  hereto  includes a
complete and correct list of each of Seller's and CRM's  employees,  job titles,
dates of employment  with Seller.  Seller has previously  furnished Buyer with a
complete and correct list of the current rates and terms of  compensation of all
such persons.. All employees are employed by Seller and CRM "at will". Except as
set forth in Schedule 4.7 hereto:

                  (i) Each of Seller and CRM is in  compliance  in all  material
respects  with  all  applicable  laws   respecting   employment  and  employment
practices,  terms and conditions of employment  and wages and hours,  and is not
engaged in any unfair labor practice;

                  (ii) no charges  with  respect to or relating to Seller or CRM
are pending before the Equal Employment  Opportunity  Commission or any state or
local agency  responsible for the prevention of unlawful  employment  practices,
and neither  Seller nor CRM has  received  notice of the intent of any  Federal,
state or local agency  responsible  for the  enforcement  of labor or employment
laws to conduct an  investigation  with  respect to or relating to the Seller or
CRM and no such investigation is in progress;

                  (iii)  none  of  Seller,   CRM,  the   Shareholders  or  their
respective  Affiliates  has been the subject of an order,  judgment or decree of
any court,  government  agency or regulatory  body that has enjoined,  barred or
suspended the Seller, CRM or any Shareholder, or any Affiliate of Seller, CRM or
any Shareholder from engaging in any type of practice or activity; and

                  (iv) all  services  performed  by  Seller  and CRM  have  been
provided in accordance with all applicable Laws in all material respects.

         4.8 Financial Information.  Attached hereto as Schedule 4.8 are the CRM
Balance  Sheet and the  income  statement  of CRM as at and for the four  months
ended  April 30,  1998  (collectively,  including  the notes  thereto,  the "CRM
Financial  Statement")  and the balance  sheets as of December 31, 1996 and 1997
and related  statements  of income,  shareholders  equity and cash flows for the
eight and twelve month  periods then ended,  respectively,  including  the notes
thereto.  The books  and  records  of CRM  accurately  and  fairly  reflect  its
activities and results of CRM, and the financial  statements and notes specified
above  accurately  and fairly  present the financial  condition,  cash flows and
results of CRM, as at the respective  dates thereof and for the periods referred
to therein,  all in accordance  with GAAP.  The CRM Balance  Sheet  reflects all
liabilities of CRM as of the Balance Sheet Date, whether absolute, accrued or


                                       11
<PAGE>


contingent, of the type required to be reflected or disclosed in a balance sheet
(or the notes thereto)  prepared in accordance with GAAP. CRM has no liabilities
or  obligations  of any nature that are not reflected on the CRM Balance  Sheet,
other than current  liabilities  (within the meaning of GAAP) incurred since the
Balance Sheet Date in the ordinary  course of business  consistent in nature and
amount  with  past  practice,  and that  are  neither  material  in  amount  nor
inconsistent with any of the representations and warranties contained herein.

         4.9 Accounts  Receivable.  All accounts  receivable of CRM reflected on
its books and records represent valid obligations for services rendered or sales
made in the  ordinary  course of  business  and are,  to the best  knowledge  of
Seller, collectible in the ordinary course of business.

         4.10  Absence of  Changes.  Since the  Balance  Sheet  Date,  except as
otherwise set forth in Schedule 4.10, each of Seller and CRM has not:

                  (i) undergone or  experienced  any material  adverse change in
its business or financial condition,  properties, assets, liabilities,  business
or other aspect of operations;

                  (ii)  suffered any damages,  destruction  or loss  (insured or
uninsured) materially and adversely affecting its ability to conduct business;

                  (iii) sold,  transferred,  encumbered  or granted any security
interest  in any of its  business,  properties  or assets  (or agreed to do so),
except in the ordinary course of its business;

                  (iv)  merged or consolidated with or been acquired by any
Person (or agreed to do so);

                  (v)   suffered or permitted any material change in the manner
of conducting business;

                  (vi)  agreed to any waiver or settlement of any material
lawsuit or dispute;

                  (vii)  made or  authorized  any loan or  advance to any Person
except for normal travel and other reasonable expense advances to employees ;

                  (viii) other than in the ordinary course of business,  granted
or  authorized  any  salary  increases,  bonuses  or other  benefits  payable to
employees or consultants;

                  (ix)  incurred  (or  agreed  to)  any  actual,  contingent  or
otherwise, indebtedness or liability, except current liabilities in the ordinary
and usual course of business;

                  (x)    made (or agreed to)  any  purchase or  lease of capital
assets;

                  (xi) paid, declared or authorized any redemption, distribution
or  dividend  with  respect  to any  member or  otherwise  with  respect  to any
ownership interest; and

                                       12
<PAGE>



                  (xii) lost, or suffered cancellation, termination or cessation
of, any  customer(s)  or client  relationship(s)  which  accounted for seven and
one-half  percent (7.5%) or more of gross revenues,  in the aggregate,  from its
business  (in the case of CRM) or the  Business  (in the case of the Seller) for
the twelve month period ended on the Balance Sheet Date.

         4.11  Undisclosed  Liabilities.  CRM  has no  material  liabilities  or
material  obligations  of any nature  (whether  accrued,  absolute,  contingent,
unasserted  or  otherwise)  other than as set forth on the CRM Balance Sheet and
except as  incurred in the  ordinary  course of  business  consistent  with past
practice since the Balance Sheet Date.

         4.12 Taxes.  Each of Seller and CRM has filed all tax returns  required
to be filed by it and has paid or has  established  an adequate  reserve for the
payment of, all Taxes  required to be paid in respect of the periods  covered by
such  returns.  Neither  Seller nor CRM is delinquent in the payment of any tax,
assessment  or  governmental  charge.  No  deficiencies  for any Taxes have been
proposed,  asserted  or assessed  against the Seller or CRM and no requests  for
waivers  of the time to assess  any Taxes  are  pending.  There are no liens for
Taxes upon any of the Assets.  None of the Seller,  CRM or the Shareholders is a
Person other than a United States Person within the meaning of the Code.

         4.13 Litigation.  Except as set forth on Schedule 4.13 attached hereto,
there  is no  suit,  action  or  proceeding  pending  against  or  (to  Seller's
knowledge)  threatened  against or affecting Seller or CRM that could reasonably
be expected to have a material  adverse effect on Seller or CRM.  Neither Seller
nor any  Shareholder  is  aware  of any  basis  for any  such  suit,  action  or
proceeding, nor is there any judgment, decree, injunction,  rule or order of any
governmental entity or arbitrator  outstanding against any Seller or CRM having,
or which in the future would have,  any such effect.  Neither Seller nor CRM, or
any Person employed by Seller or CRM, has reported a claim or potential claim to
Seller's, CRM's or such Person's professional liability insurance carrier.

         4.14  Contracts.  Neither  Seller  nor  CRM  is in  default  under  any
document,  contract,  agreement or other commitment to which it is a party or by
which it or any of its assets is bound where such default  would have a material
adverse effect on the activities,  financial  condition or results of operations
of Seller or CRM.  Each  contract or  agreement  to which the Seller or CRM is a
party is in full force and effect in  accordance  with its terms and there is no
outstanding notice of cancellation or termination in connection therewith.

         4.15 Effect of  Transaction.  No  creditor,  employee,  client or other
customer or other Person having a material business  relationship with Seller or
CRM has informed  Seller,  CRM or any  Shareholder  that such Person  intends to
change  the  relationship  because  of the  transactions  contemplated  by  this
Agreement.

         4.16  Intangible  Assets.  Schedule  4.16  hereto  includes  a true and
complete list of all fictitious names,  trademarks,  service marks, trade names,
copyrights and patents owned by CRM on the date hereof, or for which application
is pending. All such fictitious names,  trademarks,  service marks, trade names,
copyrights  and  patents  are free and clear of all  assignments,  restrictions,
encumbrances, charges or claims of infringement by third parties.


                                       13
<PAGE>



         4.17 Consents.  No consent,  order,  approval or  authorization  of, or
registration,  declaration or filing with, any court,  administrative  agency or
commission or other governmental  authority or agency,  domestic or foreign,  is
required by or with respect to the Seller,  CRM or a  Shareholder  in connection
with the  execution,  delivery and  performance  of this Agreement and the other
Transaction  Documents.  Set forth on  Schedule  4.17  hereto  are names of each
Person whose  consent is required in order to permit the transfer of an Asset to
Buyer,  the assumption by Buyer of Seller's rights  pursuant to a Contract,  and
the transfer to Buyer of the CRM Interest.

         4.18 Further Assurances. From and after the date of this Agreement (and
from and after the date of Closing  for a period of two years to the extent that
Seller shall thereafter retain any of the following), Seller shall give to Buyer
and to Buyer's  representatives,  auditors and counsel full access during normal
hours to all of the properties,  books, files, records, contracts,  licenses and
all other  documents  maintained by Seller and related to the Business and shall
furnish  to Buyer all  information  with  respect to the  Business  prior to the
Closing Date as Buyer may from time to time reasonably  request.  Seller and the
Shareholders shall use their commercially  reasonable best efforts to obtain all
consents necessary to consummate the sale,  assignment,  conveyance and delivery
of the  Assets  and the CRM  Interest  contemplated  by  this  Agreement  and to
otherwise  consummate the transactions  contemplated hereby, and to enable Buyer
to continue to conduct the  businesses  conducted  by Seller and CRM in a manner
similar to the manner in which they have previously been conducted. From time to
time after the Closing, at Buyer's request and without additional consideration,
Seller and each of the  Shareholders  agree to execute  and  deliver  such other
instruments  of  assignment  and  transfer  and take such other  action as Buyer
reasonably  may require to more  effectively  assign,  transfer  to, and vest in
Buyer  absolutely,  and to put Buyer in possession  of, any property to be sold,
assigned, transferred and delivered hereunder.

         4.19    [intentionally left blank]

         4.20 Leases and Subleases. Each lease or sublease pursuant to which the
Seller or CRM  leases or  subleases  any real or  personal  property,  either as
lessor or lessee,  is valid and binding in accordance with its terms,  and there
is not under such lease or sublease any  existing  default or breach of covenant
by the Seller or CRM or by the other party thereto, or any condition,  event, or
act that with notice or lapse of time or both would constitute default. Schedule
2.5(b) hereto  contains a true,  correct and complete list of each lease of real
property  and  personal  property  to which the  Seller or CRM is a party and in
which capacity.

         4.21  Title to Assets.  Except as set forth on  Schedule  4.21  hereto,
Buyer will receive at Closing good and marketable title to the Assets,  free and
clear of all liens,  claims,  encumbrances and security interests of any kind or
nature.  None  of  the  Assets  is the  subject  of any  pending  or  threatened
litigation.


                                       14
<PAGE>



         4.22  Title to CRM  Interest.  Buyer will  receive at Closing  good and
marketable  title to the CRM  Interest,  free and  clear of all  liens,  claims,
encumbrances and security  interests of any kind or nature.  Buyer  acknowledges
that as the owner of the CRM  Interest,  it will be  subject to the terms of the
CRM Operating Agreement.

         4.23 Employee  Benefits.  Schedule 4.23 contains a complete and correct
list of all benefit plans,  arrangements,  commitments and payroll  practices of
CRM (whether or not Employee  Benefit  Plans under  ERISA),  including,  without
limitation,  sick leave,  vacation pay,  severance pay,  salary  continuation or
disability, consulting or other compensation arrangements,  retirement, deferred
compensation,  bonus,  incentive  compensation,  stock  purchase,  stock option,
health including  hospitalization,  medical, dental and pharmacy, life insurance
and  scholarship  programs  maintained  for the benefit of any present or former
employees of CRM. Each  Employee  Benefit Plan of CRM has been  administered  in
compliance  with its terms,  and is in compliance in all material  respects with
the  applicable  provisions  of  ERISA,  the Code and all other  applicable  Law
(including,  without limitation,  funding,  filing,  termination,  reporting and
disclosure  and  continuation  coverage  obligations  pursuant to Title V of the
Consolidated Omnibus Budget Reconciliation Act of 1985, as amended).

         4.24 No  Investigation.  None of Seller,  CRM, any Shareholder or their
respective  Affiliates  nor  (to the  best of  Seller's  knowledge)  any  Person
employed by Seller or CRM is currently under  investigation  or prosecution for,
nor has Seller, CRM, any Shareholder or their respective Affiliates nor any such
Person  been  convicted  of  a  criminal   offense  related  to  fraud,   theft,
embezzlement   or  other  financial  or  unlawful   manufacture,   distribution,
prescription or dispensing of a controlled substance.

         4.25  Copies of  Documents.  Seller  has  furnished  Buyer  with  true,
complete and correct copies of: Seller's  Articles of Incorporation  and Bylaws;
all  contracts,  agreements  and  understandings  to which Seller is a party and
related to the Business; the CRM Operating Agreement; all contracts,  agreements
and  understandings to which CRM is a party (other than routine  maintenance and
similar  agreements which are not  individually or in the aggregate  material in
amount or substance to CRM or its operations); and, all contracts agreements and
understandings to which Seller is a party in its capacity as a member of CRM.

         4.26  Proper  Licensing.  Seller and CRM and each  Person  employed  or
retained  as an  independent  contractor  by Seller  and CRM are  qualified  and
licensed  to engage in  providing  the service  provided by such Person  without
restriction   or  limitation  in  the  State  of  Maryland  and  in  each  other
jurisdiction in which such Person engages in such services.

         4.27 Insurance Coverages. Each of Seller and CRM has maintained in full
force and effect  insurance  policies which are adequate in coverage amounts and
types of  risks  covered  for the  conduct  of its  business,  and all  premiums
necessary to maintain such insurance  policies have been paid or accrued in full
and are reflected on the Seller Balance Sheet and the CRM Balance Sheet.

         4.28 Prohibited Payments. None of Seller, CRM or the Stockholders, nor
any of the officers, directors, employees, agents or affiliates of Seller or CRM
has  offered,  paid or agreed  to pay to any  person or  entity,  including  any


                                       15
<PAGE>


governmental official, or solicited, received or agreed to receive from any such
person or entity, directly or indirectly, any money or anything of value for the
purpose or with the intent of  obtaining  or  maintaining  business or otherwise
affecting  the  operations,  prospects,  properties  or condition  (financial or
otherwise)  of the  Seller or CRM and which is or was in  violation  of any law,
rule or  regulation,  or is not properly and correctly  recorded or disclosed on
the books and records of the Seller or CRM.

         4.29 CRM Operating  Agreement.  The CRM Operating Agreement in the form
attached  hereto as  Exhibit  "A" is in full force and  effect,  and there is no
current breach or violation of its terms by any party thereto,  or the existence
of any  condition  which would,  if  continued,  result in a breach or violation
thereof  by any  party  thereto.  Seller  has  complied  with all the  terms and
conditions  of the CRM  Operating  Agreement,  including  but not limited to all
obligations with respect to capital  contributions  set forth in Article III. No
consent of any person is required for the transfer of the CRM Interest to Buyer.

         4.30 Investment  Representation.  Seller and each  Shareholder has such
knowledge and  experience  in financial  and business  matters so as to be fully
capable of evaluating  the merits and risks of an  investment in the Shares.  No
Shares  will be issued,  delivered  or  distributed  to any person or entity who
either (i) is a resident of the State of California or New York or (ii) is other
than an  Accredited  Investor  with respect to whom there has been  delivered to
Buyer satisfactory information confirming the status of such person or entity as
an Accredited Investor.  Seller and each Shareholder has been furnished with the
informational  materials described in Section 4.2 of the Contribution  Agreement
(collectively,  the  "Informational  Materials"),  and has read and reviewed the
Informational  Materials and  understands the contents  thereof.  Seller and the
Shareholders  have been  afforded  the  opportunity  to ask  questions  of those
persons they consider appropriate and to obtain any additional  information they
desire  in  respect  of the  Shares  and the  business,  operations,  conditions
(financial  and otherwise)  and current  prospects of the Buyer.  Seller and the
Shareholders  have consulted  their own  financial,  legal and tax advisors with
respect to the economic,  legal and tax  consequences  of delivery of the Shares
and  have  not  relied  on  COP,  COPT,  or any of  their  officers,  directors,
affiliates  or  professional  advisors for such advice as to such  consequences.
Seller and each of the Shareholders is an Accredited  Investor.  Seller and each
of the Shareholders is formed under the law of the State of Maryland.

         4.31  United  States  Person.  Each Entity and each Seller is a "United
States Person" within the meaning of Section 1445(f)(3) of the Code, as amended,
and shall execute and deliver an "Entity  Transferor"  certification (as defined
in ther Contribution Agreement) at Closing.

         4.32 Full Disclosure. All documents and other papers delivered by or on
behalf  of Seller  and each  Shareholder  in  connection  with the  transactions
contemplated  by this  Agreement  are  accurate  and  complete  in all  material
respects  and are  authentic.  No  representation  or  warranty  of  Seller or a
Shareholder  contained  in this  Agreement  or any  other  Transaction  Document
contains  any  untrue  statement  of a  material  fact or  omits to state a fact
necessary  in order to make the  statements  herein or therein,  in light of the
circumstances under which they were made, not misleading. Except as described in



                                       16
<PAGE>



this Agreement,  there is no fact known to Seller or any of the  Shareholders or
(other than proposed or enacted legislation,  proposed or enacted regulation, or
general economic or real estate industry conditions and changes) that materially
adversely  affects  or, so far as Seller  and the  Shareholders  can  reasonably
foresee,  materially threatens,  the assets,  activities,  prospects,  financial
condition or results of Seller or CRM.



ARTICLE  5.              COVENANTS OF BUYER.

          Buyer covenants and agrees to and with Seller as follows:

         5.1  Confidentiality.  Buyer  acknowledges  that the information  being
provided  by  the  Seller  and  Shareholders  is for  the  sole  purpose  of the
transactions  contemplated  hereby  and that Buyer  will keep  confidential  and
instruct Buyer's Affiliates, officers, directors, employees and advisors to keep
confidential  all  nonpublic  information  relating  to the  Seller,  except  as
required by Law and except for information  which becomes public other than as a
result of a breach of this Section 5.1.

         5.2 Financial Information.  Buyer agrees to (x) retain all of the books
and  records of the Seller  acquired  by Buyer  hereunder  and not to destroy or
dispose of any thereof for a period of three (3) years from the Closing  Date or
such longer time as may be required by Law, and (y) provide to the  Shareholders
financial  information  in its  possession or control with respect to the Seller
requested by Seller or the  Shareholders in order to comply with tax,  financial
reporting and accounting requirements.

         5.3 Proxy Statement.  As promptly as practicable after the execution of
this  Agreement,  COPT  shall  prepare  and file  with the  Securities  Exchange
Commission a Proxy  Statement  (the "Proxy  Statement")  which shall solicit the
votes of COPT's  shareholders  with  respect  to the  transactions  contemplated
hereby and by the Contribution Agreement.  The Proxy Statement shall include the
recommendation  of COPT's Board of Trustees in favor of this  Agreement  and the
transactions contemplated hereby; provided,  however, that the Board of Trustees
may modify or withdraw  such  recommendation  if it believes in good faith after
consultation  with legal  counsel that the  modification  or  withdrawal of such
recommendation  is  necessary  for the  Board of  Trustees  to  comply  with its
fiduciary obligations under applicable law.



 ARTICLE 6.                REPRESENTATIONS AND WARRANTIES OF BUYER.

         COP and COPT, jointly and severally, represent and warrant to Seller as
follows:

         6.1     Status, Power and Authority.

         COP is a limited  partnership  validly  existing  under the laws of the
State of Delaware  and has all  requisite  power to carry on its business as now
conducted.  COPT is the sole  general  partner  of COP and is a duly  formed and
validly existing Maryland real estate investment trust. Each of COP and COPT has


                                       17
<PAGE>



full power and authority and possesses all material authorizations and approvals
necessary  to enable it to execute  and  deliver  this  Agreement  and the other
Transaction  Documents  to be  executed  by  it,  and  perform  its  obligations
hereunder and  thereunder.  This Agreement and the other  Transaction  Documents
when  executed and  delivered  by COP and COPT will,  subject to approval by the
shareholders  of COPT prior to Closing,  constitute  valid and  legally  binding
obligations of each of COP and COPT, enforceable against them in accordance with
their  respective  terms,  subject to bankruptcy  and  insolvency  laws,  and to
equitable principles which may be imposed by courts.

         6.2 No Conflicts.  Subject to approval by the shareholders of COPT, the
execution,  delivery and performance of this Agreement and the other Transaction
Documents do not and will not (with or without the passage of time or the giving
of notice):  (i) violate or conflict with COP's Partnership  Agreement or COPT's
Amended and Restated  Declaration of Trust, or any Law binding upon COP or COPT;
(ii) violate or conflict with, result in a breach of, or constitute a default or
otherwise cause any loss of benefit under,  any agreement or other obligation to
which COP or COPT is a party or by which either of them (or the assets of either
of them) is bound,  or give to any other  party any rights  (including,  without
limitation,  rights of termination,  foreclosure,  cancellation or acceleration)
in, or with respect to COP or COPT; or (iii) result in,  require,  or permit the
creation or imposition of, any  restriction,  mortgage,  deed of trust,  pledge,
lien,  security  interest or other charge,  claim or  encumbrance  upon, or with
respect to, COP or COPT or the assets of either of them.

         6.3  Litigation.  There are no  actions,  suits,  claims,  proceedings,
investigations  or  inspections,  pending or (to COPT's  knowledge)  threatened,
against or affecting COPT or its Affiliates  which could have a material adverse
affect on COPT and its Afiliates  considered as a whole, and to COPT's knowledge
there are no matters of litigation or  governmental  proceedings  expected to be
brought against it or its Affiliates  which could have a material adverse affect
on the financial condition of COPT and its Affiliates considered as a whole.

         6.3  Consents.  No consent,  order,  approval or  authorization  of, or
registration,  declaration or filing with, any court,  administrative  agency or
commission or other governmental  authority or agency,  domestic or foreign,  is
required by or with respect to the COP or COPT in connection with the execution,
delivery and performance of this Agreement and the other Transaction Documents.

         6.4 SEC Reports and Financial  Statements.  The SEC Reports did not, as
of their respective dates of filing,  contain any untrue statement of a material
fact or omit to state a material fact required to be stated therein or necessary
to make the statements  contained therein,  in light of the circumstances  under
which they were made, not  misleading.  There has not been any material  adverse
change in the business of COPT since March 31, 1998.  Except as may otherwise be
set forth  therein,  the financial  statements  (including the notes thereto) of
COPT set forth in the SEC  Reports  present  fairly the  consolidated  financial
position  of  COPT  as at the  dates  set  forth  therein  and  its  results  of
operations, changes in consolidated stockholder equity and cash flows for


                                       18
<PAGE>

periods covered thereby, all in conformity with United States generally accepted
accounting principles applied on a consistent basis for such periods.

         6.5. The Shares.  The Shares to be issued at Closing will,  when issued
and delivered,  be duly authorized,  validly issued, fully paid,  non-assessable
shares of COPT free from all claims of preemptive rights.

         6.6 Tax Status.  COP has been at all times,  and  presently  intends to
continue to be,  classified as a partnership for federal income tax purposes and
not an  association  taxable as a corporation or a publicly  traded  partnership
taxable as a corporation.  COPT is now, and presently  intends to continue to be
classified,  as a real estate investment trust under Section 856 of the Internal
Revenue Code of 1986, as amended.

         6.7 Full Disclosure.  All documents and other papers delivered by or on
behalf of COP or COPT in connection with the  transactions  contemplated by this
Agreement are accurate and complete in all material  respects and are authentic.
No  representation or warranty of COP or COPT contained in this Agreement or any
other  Transaction  Document contains any untrue statement of a material fact or
omits to state a fact  necessary  in order  to make  the  statements  herein  or
therein,  in  light  of the  circumstances  under  which  they  were  made,  not
misleading. Except as described in this Agreement or in the SEC Reports there is
no fact known to COP or COPT or (other  than  proposed  or enacted  legislation,
proposed or enacted  regulation,  or general  economic  or real estate  industry
conditions and changes) that materially  adversely affects or, so far as COP and
COPT can  reasonably  foresee,  materially  threatens,  the assets,  activities,
prospects, financial condition or results of COP or COPT.

         6.8 Condition of Tangible  Assets.  COP and COPT  acknowledge  that the
tangible assets comprising a portion of the Assets are being transferred "as-is,
where-is",  and that Seller  makes no  representation  or  warranty,  express or
implied,  about the condition or fitness for any particular  purpose,  of any of
the tangible assets included as a part of the Assets.


ARTICLE 7.               CONDITIONS PRECEDENT TO OBLIGATIONS OF SELLER.

          Seller's  obligation to complete the Closing shall be  conditioned  on
the following, any of which may be waived by Seller.

         7.1 Representations and Warranties.  The representations and warranties
made by Buyer in this Agreement and all other Transaction  Documents,  or in any
exhibit,  schedule,  statement,  list or certificate furnished pursuant thereto,
shall be true  and  correct  when  made and  shall  be true and  correct  in all
material respects at and as of the time of the Closing.

         7.2  Performance  by Buyer.  Buyer shall have performed and complied in
all  material  respects  with all  agreements  and  conditions  required by this
Agreement to be performed or complied with by it prior to or at the Closing.



                                       19
<PAGE>

         7.3      Other Matters.  The  transactions  contemplated  hereby shall
be approved by all necessary action on the part of Buyer.

         7.4 Deliveries at Closing. All instruments, documents, certificates and
other items  required to be delivered to Seller  pursuant to Section 10.2 of the
Agreement shall have been delivered to Buyer at or prior to the Closing Date.

         7.5 Shareholder  Approval and Other Closings.  The Shareholders of COPT
shall have approved the transactions contemplated hereby and by the Contribution
Agreement  and  the  Development   Agreements.   Immediately  preceding  Closing
hereunder, there shall be a closing pursuant to the Contribution Agreement.


 ARTICLE 8.                CONDITIONS PRECEDENT TO BUYER'S OBLIGATIONS.

          Buyer's obligation to complete the Closing shall be conditioned on the
following, any of which may be waived by Buyer.

         8.1 Representations and Warranties.  The representations and warranties
made by Seller and the Shareholders in this Agreement and all other  Transaction
Documents, or in any exhibit, schedule, statement, list or certificate furnished
pursuant  thereto,  shall be true and  correct  when  made and shall be true and
correct in all material respects at and as of the time of the Closing.

         8.2  Performance  by  Seller  and  the  Shareholders.  Seller  and  the
Shareholders shall have performed and complied in all material respects with all
agreements and conditions required by this Agreement to be performed or complied
with by them prior to or at the Closing.

         8.3 Federal and State Licenses, Permits and Authorizations. Buyer shall
have received or have been granted any and all necessary  licenses,  permits and
authorizations by the appropriate local,  state and federal government  agencies
in  order  for  Buyer  to  purchase  the  Assets  and  the  CRM  Interest   (the
"Authorizations").  Seller and the Shareholders shall cooperate and employ their
best efforts to assist Buyer in receiving the Authorizations.

         8.4  Other  Matters.  The  transactions  contemplated  hereby  shall be
approved by all necessary  corporate action on the part of the Seller, and there
shall have been no material change in any Law or regulation  affecting Seller or
CRM.

         8.5 Deliveries at Closing. All instruments, documents, certificates and
other items  required to be delivered  to Buyer  pursuant to Section 10.1 of the
Agreement shall have been delivered to Buyer at or prior to the Closing Date.

         8.6 Buyer's  Rights With Respect to CRM Interest.  Buyer shall have the
right not to purchase the CRM Interest at Closing, if Buyer is not satisfied for
any reason whatsoever with the documents, agreements and instruments relating to
such  transfer.  Buyer may  exercise  this  right,  in its sole  discretion,  by
notifying Seller in writing of its intention not to purchase the CRM Interest at
any time up to completion of the closing of the Contribution Agreement. If Buyer



                                       20
<PAGE>

elects not to purchase the CRM Interest: (i) the Purchase Price shall be reduced
to Shares  representing  an  aggregate  value of Seven  Hundred  Fifty  Thousand
Dollars  ($750,000.00);  (ii) the amount set forth in Section 9.7 below shall be
changed to Twenty Thousand Dollars ($20,000.00);  and (iii) this Agreement shall
otherwise continue in full force and effect.

         8.7 Shareholder  Approval and Other Closings.  The Shareholders of COPT
shall have approved the transactions contemplated hereby and by the Contribution
Agreement  and  the  Development   Agreement.   Immediately   preceding  Closing
hereunder, there shall be a closing pursuant to the Contribution Agreement.


ARTICLE 9.            INDEMNIFICATION.

         9.1 Basic Provision.  The Sellers and the  Shareholders  hereby jointly
and severally agree to indemnify, defend and hold harmless Buyer, its Affiliates
and their respective partners, directors, officers, shareholders,  employees and
agents and the successors and assigns of each of the foregoing (individually, an
"Indemnitee" and collectively, the "Indemnitees"),  from, against and in respect
of the amount of any and all Deficiencies.

         9.2      Definitions of "Deficiencies.   As used herein, "Deficiencies"
means:

         (i) any and all losses,  damages, costs and expenses resulting from any
misrepresentation,  breach of warranty or representation, or any non-fulfillment
of any warranty, representation,  covenant or agreement on the part of Seller or
any Shareholder contained herein;

         (ii) any and all losses, damages, costs and expenses resulting from any
misrepresentation  contained  in any  statement,  report,  certificate  or other
document  or  instrument  delivered  to  Buyer  pursuant  to this  Agreement  or
contained in any Schedule or Exhibit hereto;

         (iii) any and all losses,  damages,  costs and  expenses  resulting  to
Indemnitee by reason of any claim, debt,  liability or obligation or any alleged
claim,  debt,  liability  or  obligation  of  CRM,  Seller  or  any  Shareholder
(including  but  not  limited  to any  claim  for  malpractice  or  professional
liability),  whether  known or unknown,  accrued or  contingent,  except for the
Assumed Liabilities;

         (iv) any and all losses, damages, costs and expenses resulting from all
actions and conduct occurring on or prior to the Closing Date by or on behalf of
CRM,  Seller or the  Shareholders,  including  but not  limited to  actions  and
conduct of Seller and its employees, customers or agents; and

          (v) any and all actions,  suits,  proceedings,  demands,  assessments,
judgments, reasonable attorneys' fees, costs and expenses incident to any of the
foregoing.


                                       21
<PAGE>


         9.3  Procedures  for Third  Party  Claims.  In the event that any claim
shall be asserted by any individual or entity against Buyer which, if sustained,
would result in a Deficiency,  Buyer, within a reasonable time after learning of
such claim,  shall notify Seller and the  Shareholders of such claim,  and shall
extend to Seller and the Shareholders a reasonable opportunity to defend against
such claim, at the Sellers' and the Shareholders' sole expense and through legal
counsel acceptable to Buyer,  provided that Seller and the Shareholders  proceed
in good faith,  expeditiously and diligently to defend such claim.  Buyer shall,
at its  option  and  expense,  have the  right  to  participate  in any  defense
undertaken  by  Seller  and  the  Shareholders  with  legal  counsel  of its own
selection.  No  settlement  or  compromise  of any claim  which may  result in a
Deficiency  may be made by Seller or any  Shareholder  without the prior written
consent of Buyer unless prior to such  settlement or  compromise  (i) Seller and
the  Shareholders  acknowledge  in writing  their  obligation to pay in full the
amount of the settlement and all  associated  expenses,  (ii) Buyer is furnished
with security reasonably  satisfactory to Buyer that Seller and the Shareholders
will in fact pay such amount and expenses and (iii) Seller and the  Shareholders
obtain a written release from the claimant, in a form reasonably satisfactory to
Buyer, of the Buyer from all liability,  past, present and future,  arising from
or in connection with the claim.

         9.4  Payment of  Deficiencies.  In the event that Buyer  discovers  any
Deficiency,  Buyer shall give written notice to Seller and the  Shareholders  of
the nature  and amount of the  Deficiency.  Seller and the  Shareholders  hereby
agree to pay the amount of such  Deficiency  to Buyer in cash within thirty (30)
days after  written  notice from Buyer which  reasonably  details the nature and
amount of the Deficiency.  Any amounts required to be paid which are not paid by
Seller and the  Shareholders  when due under this Article 9 shall bear  interest
from the due date  thereof  until the date paid at a rate of interest  per annum
that is equal to the Prime Rate. At Buyer's option, Buyer may off-set any unpaid
Deficiency or portion thereof against any obligation Buyer may have to any party
hereto.

         9.5  Provisions  Not  Exclusive.  The  indemnification  obligations  of
Seller, the Shareholders and Buyer contained herein, including any rights of set
off as described herein, are not intended to waive or preclude any other claims,
rights or remedies which may exist at law (whether statutory or otherwise) or in
equity with  respect to the matters  covered by the  indemnifications  described
herein.

         9.6 Time Limit on Certain Claims. No claim for  indemnification  may be
asserted  pursuant to a Deficiency  described in Section 9.2,  unless  notice of
such claim shall have been given within  eighteen  months after the Closing Date
to the person from whom such indemnification may be sought (except that the cost
of items  described in Section 9.2(v) which are based on claims for which notice
has been given in such eighteen month period shall be payable regardless of when
incurred);   provided,   however,   that  if  the   Deficiency  is  based  on  a
misrepresentation  or breach contained in Sections 4.12, 4.21, 4.22 or 4.30, the
claim for indemnification  with respect thereto shall have been given within the
later of three  years  after the  Closing  Date or the  statute  of  limitations
applicable to such underlying claim.

         9.7 Limit on  Amounts.  No claim for  indemnification  may be  asserted
pursuant to this Article 9 against Seller and the Shareholders until the


                                       22

<PAGE>

aggregate amount of Deficiencies for claims which then may be asserted hereunder
exceeds Fifty thousand Dollars ($50,000.00), whereupon all such Deficiencies may
be claimed.

         9.8  Indemnification  by COP and COPT.  COP and COPT shall  jointly and
severally  indemnify,   protect,   defend  and  hold  Seller  and  each  of  the
Shareholders (the "Seller  Indemnified  Parties")  harmless from and against any
claims, losses, demands,  liabilities,  suits, costs and damages suffered by the
Seller Indemnified Parties incurred, arising against, or suffered by, the Seller
Indemnified  Parties as a consequence  of (i) any breach of any  representation,
warranty or covenant made in this  Agreement by COP or COPT, or (ii) the failure
of COP or COPT to satisfy any of the Assumed Liabilities.


ARTICLE 10.          DELIVERIES AT CLOSING.

         10.1  Deliveries  by Seller and the  Shareholders  at  Closing.  If not
previously  delivered,  at Closing Seller and the Shareholders  shall deliver or
cause to be delivered to Buyer each of the following:

         (a) all contractual assignments, third-party consents, permits, waivers
and governmental  approvals,  as well as evidence of the completion of all other
transactions   necessary  or  appropriate  for  consummation  by  Buyer  of  the
transactions contemplated by this Agreement and the other Transaction Documents,
in form and substance reasonably satisfactory to Buyer;

         (b)  resolutions  of Seller's  Board of Directors and the  Shareholders
authorizing  the execution,  delivery and  performance of this Agreement and the
other Transaction Documents to be executed and performed by Seller;

         (c) duly executed bills of sale, articles of transfer,  assignments and
other  documents  evidencing  the transfer of the Assets and the CRM Interest to
Buyer, in form reasonably satisfactory to Buyer;

         (d) an  opinion  of  Daniel  R.  Skowronski,  counsel  for the  Seller,
addressed  to  Buyer  and  dated  the  date  of the Closing, in the same form as
provided for in Section 16.1.3  of  the Contribution  Agreement,  except that no
opinion will  be  rendered  with respect to the transfer of the interest in CRM
without obtaining the consent of KLNB Inc.;

         (e) a certificate executed by the chief executive officer of Seller and
by  each  Shareholder  to  the  effect  that  all  conditions  precedent  to the
obligation of the Seller to close  hereunder have been satisfied or waived,  and
that the  representations and warranties of the Seller in the Agreement are true
and correct as of the Closing Date;

         (f) Good Standing  Certificates  reflecting  each of Seller's and CRM's
good standing issued by the State of Maryland as of a date immediately  prior to
the Closing; and

         (g) such other certificates,  instruments,  documents, agreements, etc.
as may be  reasonably  necessary  or  appropriate  to  effect  the  transactions
contemplated hereby.



                                       23
<PAGE>

         10.2 Deliveries by Buyer at Closing.  If not previously  delivered,  at
Closing  Buyer  shall  deliver or cause to be  delivered  to Seller  each of the
following:

         (a)      the Shares;

         (b) a  resolution  of  COPT's  Trustees,  for COPT and as sole  general
partner of COP,  authorizing  the  execution,  delivery and  performance of this
Agreement  and the other  Transaction  Documents to be executed and performed by
COPT and COP;

         (c) a  certificate  executed  by COPT,  for  COPT  and as sole  general
partner of COP, to the effect that all conditions precedent to the obligation of
the COP to  close  hereunder  have  been  satisfied  or  waived,  and  that  the
representations  and  warranties  of COP and COPT in the  Agreement are true and
correct as of the Closing Date;

                                       24
<PAGE>



         (d) an  opinion  of counsel  for COP and COPT  addressed  to Seller and
dated the date of the Closing, as to the matters described in Sections 6.1, 6.2,
6.3 and 6.5 hereof in form and substance reasonably satisfactory to Seller; and

         (e)      such  other  certificates, instruments, documents, agreements,
etc. as  may  be  reasonably necessary or appropriate to effect the transactions
contemplated hereby.

ARTICLE 11.            TERMINATION; REMEDIES.

         11.1  Termination  by  Buyer.  This  Agreement  may be  terminated  and
canceled at any time prior to the Closing by the Buyer,  upon written  notice to
the Seller,  if any of the following  circumstances or events continues for more
than ten (10) business days after Buyer has provided  written  notice thereof to
Seller of its intention to terminate this Agreement:

                  (a) any of the  representations or warranties of the Seller or
the Shareholders  contained herein or in any other Transaction Document shall be
inaccurate or untrue in any material respect;

                  (b)  any  material   obligation,   term  or  condition  to  be
performed,  kept or observed by Seller or any Shareholder hereunder has not been
performed,  kept or  observed  in any  material  respect at or prior to the time
specified in this Agreement; or

                  (c) any one of the conditions precedent to Buyer's obligations
to complete Closing  hereunder as set forth in Article 7 has not been satisfied,
or waived by Buyer in writing,  at or before the  Closing  unless the failure of
condition is the result of a material breach of this Agreement by Buyer.

         11.2  Termination  by Seller.  This  Agreement  may be  terminated  and
canceled at any time prior to the Closing by the Seller,  upon written notice to
the Buyer,  if any of the  following  circumstances  or events  continues  after
Seller has provided ten (10) business  days' written  notice thereof to Buyer of
its intention to terminate this Agreement:

                  (a)      any of the  representations  or   warranties  of  the
Buyer  contained  herein  or in any Transaction Document  shall be inaccurate or
untrue in any material respect;

                  (b)  any  material   obligation,   term  or  condition  to  be
performed,  kept or observed by Buyer hereunder has not been performed,  kept or
observed  in any  material  respect  at or prior to the time  specified  in this
Agreement; or

                  (c)  any  one  of  the   conditions   precedent   to  Seller's
obligations to complete Closing hereunder as set forth in Article 6 has not been
satisfied,  or waived by Seller in writing,  at or before the Closing unless the
failure of  condition  is the result of a material  breach of this  Agreement by
Seller or a Shareholder.

         11.3 Termination by Agreement.  This Agreement may be terminated at any
time by mutual written agreement of Buyer and Seller, and shall be automatically
terminated upon termination of the Contribution Agreement.

         11.4 Effect of Termination.  All  obligations of the Parties  hereunder
shall  cease upon any  termination  pursuant  to  Sections  11.1,  11.2 or 11.3,
provided,  however,  that (x) the  provisions  of this Article 11,  Section 2.3,
Section  3.4 and  Section  5.1 hereof  shall  survive  any  termination  of this
Agreement; and (y) nothing herein shall relieve any party from any liability (at
law or in equity) for a material error or omission in any of its representations
or warranties  contained  herein or a material failure to comply with any of its
covenants, conditions or agreements contained herein, if such error, omission or
failure was willful or  deliberate,  but if such error,  omission or failure was
not willful or  deliberate,  the  liability  of the  responsible  party shall be
limited to out-of-pocket expenses incurred by the other party(ies) in connection
with  negotiating,  preparing and entering into this  Agreement and carrying out
the transactions contemplated hereby.

ARTICLE 12.  NOTICES.  Any  notice,  demand or request  which may be  permitted,
required  or  desired  to be given  in  connection  therewith  shall be given in
writing and directed to Seller and the Shareholders and Buyer as follows:

                          Seller and the Shareholders:

                                    Constellation Real Estate, Inc.
                                    8815 Centre Park Drive - Suite 400
                                    Columbia, MD   21045
                                    Attention:       General Counsel
                                    Telecopy:        410-740-1174
                                       and

                                    Constellation Holdings, Inc.
                                    250 West Pratt Street


                                       25
<PAGE>


                                  Baltimore, MD   21201-2423
                                    Attention:       Dan R. Skowronski, Esquire
                                    Telecopy: 410-783-3632


                          With a copy to its attorneys:

                                    Stephen L. Owen, Esquire
                                    Piper & Marbury LLP
                                    36 South Charles Street
                                    Baltimore, MD   21201-3018
                                    Telecopy: 410-539-0489


                                     Buyer:

                                    Corporate Office Properties Trust
                                    One Logan Square, Suite 1105
                                    Philadelphia, PA   19103
                                    Attention:       Clay W. Hamlin, III
                                                     President and Chief
                                                     Executive Officer
                                    Telecopy: 215-567-1907

                                    With a copy to its attorneys:

                                    F. Michael Wysocki, Esquire
                                    Saul, Ewing, Remick & Saul LLP
                                    Centre Square West
                                    1500 Market Street - 38th Floor
                                    Philadelphia, PA   19102
                                    215-972-7139

Notices shall be deemed  properly  delivered and received when and if either (i)
personally delivered, including via facsimile; or (ii) on the first business day
after  deposit  with a  commercial  overnight  courier for  delivery on the next
business  day.  Any party may  change its  address  for  delivery  of notices by
properly notifying the others pursuant to this Article 12.



ARTICLE 13.              MISCELLANEOUS PROVISIONS.

         13.1  Entire  Agreement;  Counterparts.  This  Agreement  is the entire
agreement  between the parties hereto with respect to the sale of the Assets and
the CRM Interest and  supersedes all prior and  contemporaneous  communications,
representations,  agreements,  discussions and  understandings,  whether oral or
written,  between  the  parties  hereto,  including,   without  limitation,  any
financial or other projections,  valuations or predictions regarding the Seller,
the  Assets  or the CRM  Interest.  There  are no oral  or  written  agreements,
understandings, representations or warranties between the parties hereto with


                                       26

<PAGE>

respect to the subject matter hereof other than those set forth or  contemplated
in this Agreement.  This Agreement may be executed in two or more  counterparts,
each of which  shall be  deemed an  original,  but all of which  together  shall
constitute one and the same instrument.

         13.2  Headings.  The  headings  contained  in  this  Agreement  and the
Schedules and Exhibits are for reference  purposes only and shall not affect the
meaning or interpretation of this Agreement. Reference to Sections, Schedules or
Exhibits  are  to  portions  of  this  Agreement  unless  the  context  requires
otherwise.

         13.3  Assignment and Amendment of Agreement.  This  Agreement  shall be
binding  on and  inure  to the  benefit  of the  parties  hereto,  their  heirs,
executors, administrators,  successors and assigns; provided, however, that this
Agreement  shall not be  assignable or  transferable  by Seller or a Shareholder
without  the prior  written  consent of Buyer,  or by Buyer  without the written
consent of Seller,  except that Buyer may assign  some or all of Buyer's  rights
and obligations  under this Agreement  without such prior written consent to any
Affiliate of Buyer.  Neither this  Agreement  nor any  provisions  hereof may be
waived, modified,  amended,  discharged or terminated except by an instrument in
writing  signed  by the party  against  which the  enforcement  of such  waiver,
modification,  amendment,  discharge or termination is sought,  and then only to
the extent set forth in such instrument.

         13.4  Commercially  Reasonable  Best Efforts.  Subject to the terms and
conditions of this  Agreement  each party will use its  commercially  reasonable
best  efforts to cause the  Closing to occur.  Seller and Buyer  shall use their
commercially  reasonable,  diligent and good faith efforts,  and shall cooperate
with and assist each other in their efforts,  to obtain any and all consents and
approvals  of  third  parties  (including,  but  not  limited  to,  governmental
authorities) to the transaction contemplated hereby, and to otherwise perform as
may be  necessary  or  otherwise  reasonably  requested  by the  other  party to
effectuate and carry out the purposes of, this Agreement.

         13.5  Applicable  Law. This Agreement  shall be construed in accordance
with the laws of the State of Maryland without regard to principles of conflicts
of law.

         13.6 No Third Party  Rights.  This  Agreement is not intended and shall
not be  construed  to create any rights in any persons  other than  Seller,  the
Shareholders and Buyer and their permitted assignees, and no Person shall assert
any rights as third party beneficiary hereunder.

         13.7  Incorporation  of  Schedules  and  Exhibits.  The  Schedules  and
Exhibits  attached  hereto are  incorporated  into this  Agreement  and shall be
deemed a part hereof as if set forth herein in full.  Reference  herein to "this
Agreement" and the words "herein," "hereof' and words of similar import refer to
this Agreement including its Schedules and Exhibits as an entirety. In the event
of any conflict  between  provisions of this  Agreement and any such Schedule or
Exhibit, the provisions of this Agreement shall control.

         13.8 Survival. The covenants, rights, obligations,  representations and
warranties of each of the parties hereunder shall survive the Closing subject to
the limitations set forth in this Agreement.



                                       27
<PAGE>



         13.9  Waiver.  The failure of any party at any time or times to enforce
its rights under such  provisions,  strictly in accordance with the same,  shall
not be construed as having created a custom in any way or manner contrary to the
specific provisions of this Agreement or as having in any way or manner modified
or waived the same.

         13.10  Enforcement.  Each of the Parties hereto shall have the right at
all times to enforce the provisions of this Agreement in strict  accordance with
its terms and to pursue  remedies for breach by any legal and  equitable  means,
including by an action for specific performance,  notwithstanding any conduct or
custom on its part in refraining from doing so at any time or times.

         13.11 Litigation.  Seller,  the Shareholders and Buyer waive all rights
to a jury trial with respect to any disputes relating to this Agreement, whether
arising before or after Closing.  In the event of litigation between the parties
with respect to this Agreement,  the performance of their respective obligations
hereunder or the effect of a termination under this Agreement,  the losing party
shall pay all costs and expenses  incurred by the prevailing party in connection
with such litigation,  including, but not limited to, reasonable attorneys' fees
of  counsel  selected  by the  prevailing  party.  The  parties  hereby  further
acknowledge  and  agree  that  in the  event  of  litigation  between  them,  as
contemplated  above, and the resolution of that litigation  through  compromise,
settlement,  or partial  judgment,  the court  before which such  litigation  is
initially  brought  shall  have the right to  allocate  responsibility,  between
Seller and the  Shareholders  on the one hand,  and Buyer on the other,  for all
costs and expenses (including,  but not limited to, attorneys'  reasonable fees)
incurred  by all  parties in the  pursuit of that  litigation  resolved  through
compromise,  settlement or partial  judgment.  Notwithstanding  any provision of
this Agreement to the contrary,  the obligations of the parties under this shall
survive termination of this Agreement and the Closing, if applicable.


         13.12  Publicity.  Seller,  the  Shareholders  and Buyer  agree that no
public release or announcement  concerning the transactions  contemplated hereby
shall be issued by either party without the prior written  consent of both Buyer
and Seller,  but in no event shall financial terms be disclosed,  except as such
release or announcement may be required by law or court order, in which case the
party required to make the release or  announcement  shall allow the other party
reasonable  time to comment on such release or  announcement  in advance of such
issuance.



                                       28

<PAGE>

         13.13 Brokerage.  Seller and the Shareholders  represent and warrant to
Buyer that none of them,  and Buyer  represents  and  warrants to Seller and the
Shareholders  that  neither of them,  has dealt  with any  brokers or finders in
connection with this  transaction  and that no broker,  finder or other party is
entitled to a commission, finder's fee or other similar compensation as a result
hereof,  except Legg Mason Real Estate Services,  Inc. under separate  agreement
with  Buyer.  Buyer  shall pay to Legg  Mason Real  Estate  Services,  Inc.  the
compensation  payable to it with  respect to this  transaction  pursuant to such
agreement. Seller and the Shareholders hereby indemnify,  protect and defend and
hold Buyer  harmless  from and  against  all losses,  claims,  costs,  expenses,
damages (including,  but not limited to, attorneys' fees of one counsel selected
by Buyer)  resulting or arising  from the claims of any broker,  finder or other
such party,  claiming by, through or under the acts or agreements of Seller or a
Shareholder.  Buyer  hereby  indemnifies,  defends  and  holds  Seller  and  the
Shareholders  harmless  from and against all losses,  claims,  costs,  expenses,
damages (including,  but not limited to, attorneys' fees of one counsel selected
by the  Seller and  Shareholders)  resulting  or arising  from the claims of any
broker,  finder or other  such  party  claiming  by,  through  or under  acts or
agreements of Buyer.  This Section 13.13 shall survive any  termination  of this
Agreement and the Closing, if applicable.



                                       29
<PAGE>


         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed under seal as of the date first written above.

                                    CORPORATE OFFICE PROPERTIES TRUST

                                    By:    /s/ Clay W. Hamlin, III
                                         Clay W. Hamlin, III, President and
                                           Chief Executive Officer:

                                    CORPORATE OFFICE PROPERTIES, L.P.

                                     By:  Corporate Office Properties Trust,
                                          its sole general partner


                                     By:   /s/ Clay W. Hamlin, III
                                         Clay W. Hamlin, III, President and
                                          Chief Executive Officer:





                                    CONSTELLATION REAL ESTATE, INC.


                                    By:  /s/ Randall M. Griffin
                                    Title:   Randall M. Griffin
                                                 President



                                    SHAREHOLDERS:

                                    KMS OLDCO,INC.


                                     By:   /s/ Randall M. Griffin
                                     Title:    Randall M. Griffin
                                                 President


                                    CONSTELLATION REAL ESTATE GROUP, INC.


                                    By:    /s/ Randall M. Griffin
                                     Title:    Randall M. Griffin
                                                 President  
                                    

                                       30
<PAGE>



SCHEDULES AND EXHIBITS

SCHEDULES:

         2.1(c)   Excluded Assets
         2.2      Allocation of Purchase Price
         2.5(b)   Agreements, Leases and Equipment Leases to be Assumed by Buyer
         4.5      Subsidiaries, Joint Ventures, etc.
         4.7      Employees and Labor Matters
         4.8      Financial Statements
         4.10     Changes Since Balance Sheet Date
         4.13     Litigation
         4.16     Intangible Assets
         4.17     Third Party Consents Required
         4.21     Encumbrances
         4.23     Employee Benefit Plans


EXHIBITS:

         "A"      CRM Operating Agreement
         "B"      Form of Opinion of counsel to Seller



                                       31




                          REGISTRATION RIGHTS AGREEMENT


         THIS  REGISTRATION  RIGHTS  AGREEMENT  (this  "Agreement")  is made and
entered into as of September28,  1998  by  Corporate  Office  Properties  Trust,
a Maryland real estate investment trust (the "Company"),  for the benefit of (x)
persons issued shares of Common Stock of the Company  ("Common  Stock") pursuant
to  the  Contribution  Agreement,  the  Asset  Contribution  Agreement  and  the
Development  Agreements  (each, as defined below),  (y) persons issued shares of
Convertible  Preferred Stock of the Company  ("Preferred Stock") pursuant to the
Contribution  Agreement,  the Asset  Contribution  Agreement and the Development
Agreements, and (z) the respective successors,  assigns, transferees and estates
of  the  persons   identified  in  clauses  (x)  and  (y)  (herein  referred  to
collectively as the "Holders" and individually as a "Holder").  The Common Stock
and  Preferred  Stock  issued and to be issued to the  Holders  pursuant  to the
Contribution  Agreement,  the Asset  Contribution  Agreement and the Development
Agreements are herein sometimes collectively called the "Stock."

         WHEREAS,  on the date hereof  certain  Holders have become the owner of
Stock  upon the  transfer  of certain  partnership  interests  and other  assets
pursuant to the Contribution Agreement dated as of May 14, 1998 by and among the
Company,  Corporate Office  Properties,  L.P. ("COP") and the Persons identified
therein  as  "Sellers",  as the same may at any time be  amended,  modified  and
supplemented and in effect (the "Contribution Agreement");

         WHEREAS,  on the date hereof  certain  Holders have become the owner of
Stock  upon the  transfer  of  certain  membership  interests  and other  assets
pursuant to the Service Company Asset Contribution Agreement dated as of May 14,
1998 by and  among  COP and the  Persons  identified  therein  as  "Seller"  and
"Shareholders",   as  the  same  may  at  any  time  be  amended,  modified  and
supplemented and in effect (the "Asset Contribution Agreement");

         WHEREAS,  after the date hereof certain Holders may become the owner of
Stock  upon the  transfer  of certain  partnership  interests  and other  assets
pursuant to two Development  Properties  Acquisition Agreements each dated as of
May 14, 1998 by and among the Company, COP and the Persons identified therein as
"Sellers", as the same may at any time be amended, modified and supplemented and
in effect (the "Development Agreements");

         WHEREAS,  pursuant to the Company's Amended and Restated Declaration of
Trust,  the Holders of shares of Preferred  Stock have the right to convert them
into shares of Common Stock;

         WHEREAS,  on the date  hereof,  the Common  Stock is publicly  held and
traded  and  the  Company  is an  issuer  which  is  subject  to  the  reporting
requirements  of the  Securities  Exchange Act of 1934,  as amended from time to
time (the "Exchange Act");

         WHEREAS,  in  connection  with the  foregoing,  the Company has agreed,
subject to the terms, conditions and limitations set forth in this Agreement, to
provide the Holders  with  certain  registration  rights in respect of shares of
Common Stock issued either (x) pursuant to the Contribution Agreement, the Asset
Contribution Agreement or the Development Agreements,  or (y) upon conversion of
shares of Preferred Stock issued  pursuant to the  Contribution  Agreement,  the
Asset Contribution Agreement or the Development Agreements.


<PAGE>

         NOW,  THEREFORE,  the Company for the benefit of the Holders  agrees as
follows:

         Section 1.         DEFINITIONS.

         As used in this  Agreement,  the  following  capitalized  defined terms
shall have the following meanings:

         Asset Contribution Agreement:  As set forth in the preamble.

         Commission:  The Securities and Exchange Commission.

         Common Stock:  Shares of common stock, $.01 par value, of the Company.

         Contribution Agreement:  As set forth in the preamble.

         Development Agreements:   As set forth in the preamble.

         Exchange Act:  As set forth in the preamble.

         Holder or Holders:  As set forth in the preamble.

         Majority Holders:  At any time,  Holders of Registrable  Securities and
shares of Preferred Stock then convertible  into Registrable  Securities who, if
all such  Preferred  Stock were  converted,  would  then hold a majority  of the
Registrable Securities.

         Minimum  Registrable Amount:  At any date of determination, Registrable
Securities having an aggregate fair market value of at least $3 million.

         NASD:  The National Association of Securities Dealers, Inc.

         Person:  Any individual, partnership, corporation, trust or other legal
entity.

         Preferred Stock:[Shares of Convertible Preferred Stock, par value ____]
of the Company.

         Prospectus:   A  prospectus  included  in  a  Registration   Statement,
including  any  preliminary  prospectus,  and any such  prospectus as amended or
supplemented  by any  prospectus  supplement  with  respect  to the terms of the
offering  of  any  portion  of  the  Registrable   Securities  covered  by  such
Registration  Statement,  and by all other  amendments  and  supplements to such
prospectus,  including post-effective amendments, and in each case including all
material incorporated by reference therein.

         Registrable Securities:  The shares of Common Stock (i) issued pursuant
to the terms of the Contribution Agreement, the Asset Contribution Agreement and
the Development Agreements,  and (ii) issued and issuable upon conversion of the
shares of  Preferred  Stock  issued  pursuant  to the terms of the  Contribution
Agreement,  the Asset  Contribution  Agreement and the  Development  Agreements.
Registrable  Securities  shall  not  include  (x)  Common  Stock  as to  which a
Registration  Statement  shall have become  effective  under the  Securities Act
pursuant  to  Section  2, 3 or 4 of this  Agreement  and which  shall  have been
disposed  of under  such  Registration  Statement,  (ii)  Common  Stock  sold or

                                       2

<PAGE>


otherwise  distributed  pursuant to Rule 144 under the  Securities Act and (iii)
Common Stock as to which  registration  under the Securities Act is not required
to permit the sale  thereof  to the  public by a Holder at any time and  without
application  of any  volume or other  limitations  imposed by Rule 144 under the
Securities Act.

         Sale Period:  The 60-day period  immediately  following the filing with
the Commission by the Company of an annual report of the Company on Form 10-K or
a  quarterly  report of the  Company  on Form 10-Q or such  other  period as the
Company may determine.

         Securities  Act:  The  Securities  Act of 1933, as amended from time to
time.

         Shelf  Registration  Statement:   shall  mean  a  "shelf"  registration
statement of the Company and any other entity  required to be a registrant  with
respect to such shelf registration statement pursuant to the requirements of the
Securities Act which covers all of the  Registrable  Securities  then issued and
outstanding  or which may  thereafter  be issued  pursuant  to the  Contribution
Agreement,  the Asset Contribution Agreement or the Development Agreements on an
appropriate  form under Rule 415 under the  Securities  Act, or any similar rule
that may be adopted by the  Commission,  and all amendments  and  supplements to
such registration statement,  including post-effective  amendments, in each case
including  the  Prospectus  contained  therein,  all  exhibits  thereto  and all
materials incorporated by reference therein.



         Section 2.         SHELF REGISTRATION UNDER THE SECURITIES ACT.

                  (a) Filing of Shelf Registration Statement.  Within six months
following,  the  date  hereof,  the  Company  shall  cause  to be  filed a Shelf
Registration  Statement  providing  for the  sale by the  Holders  of all of the
Registrable  Securities  in  accordance  with the terms  hereof and will use its
reasonable  best  efforts  to cause  such  Shelf  Registration  Statement  to be
declared  effective by the SEC as soon as  reasonably  practicable.  The Company
agrees  to use its  reasonable  best  efforts  to keep  the  Shelf  Registration
Statement continuously effective under the Securities Act until such time as the
aggregate  number  of  Registrable  Securities  outstanding  (computed  for this
purpose as if all outstanding shares of Preferred Stock have been converted into
Common Stock) is less than 5% of the aggregate number of Registrable  Securities
outstanding  on the date hereof  (assuming  all Stock  issuable  pursuant to the
Development  Agreements  has been issued),  and further  agrees to supplement or
amend  the  Shelf  Registration  Statement,  if and as  required  by the  rules,
regulations  or  instructions  applicable to the  registration  form used by the
Company for such Shelf Registration Statement or by the Securities Act or by any
other rules and regulations  thereunder for Shelf Registration.  Each Holder who
sells shares of Common Stock as part of the Shelf  Registration  shall be deemed
to have agreed to all of the terms and  conditions of this Agreement and to have
agreed to perform any and all obligations of a Holder hereunder.

                  (b) Inclusion in Shelf Registration Statement.  Not later than
30 days prior to filing the Shelf  Registration  Statement with the  Commission,
the Company  shall  notify each Holder of its  intention to make such filing and
request  advice from each such Holder as to whether such Holder  desires to have
Registrable  Securities  held by it or which it is entitled to receive not later
than the last day of the first Sale Period  occurring  in whole or in part after
the date of such notice  included in the Shelf  Registration  Statement  at such
time. Any such Holder who does not provide the information  reasonably requested

                                       3

<PAGE>


by the Company in connection with the Shelf  Registration  Statement as promptly
as practicable after receipt of such notice,  but in no event later than 20 days
thereafter, shall not be entitled to have its Registrable Securities included in
the Shelf  Registration  Statement at the time it becomes  effective,  but shall
have the right  thereafter  to deliver to the Company a  Registration  Notice as
contemplated by Section 3(b) to have such Registrable Securities included in the
Shelf Registration Statement by post effective amendment.

         Section 3.         SHELF REGISTRATION PROCEDURES.

         In connection  with the  obligations of the Company with respect to the
Shelf Registration Statement pursuant to Section 2 hereof, the Company shall:

                  (a) prepare and file with the SEC,  within the time period set
forth in Section  2(a)  hereof,  a Shelf  Registration  Statement,  which  Shelf
Registration  Statement (i) shall be available  for the sale of the  Registrable
Securities in accordance  with the intended method or methods of distribution by
the selling  Holders  thereof and (ii) shall  comply as to form in all  material
respects with the requirements of the applicable form.

                  (b) subject to the last three  sentences  of this Section 3(b)
and to Section  3(i)  hereof,  (i)  prepare  and file with the  Commission  such
amendments and post-effective  amendments to the Shelf Registration Statement as
may be  necessary to keep the Shelf  Registration  Statement  effective  for the
applicable period; (ii) cause each Prospectus to be supplemented by any required
prospectus  supplement,  and as so supplemented to be filed pursuant to Rule 424
or any similar rule that may be adopted under the Securities  Act, (iii) respond
promptly to any comments  received from the Commission with respect to the Shelf
Registration Statement, or any amendment, post-effective amendment or supplement
relating thereto; and (iv) comply with the provisions of the Securities Act with
respect to the disposition of all securities  covered by the Shelf  Registration
Statement during the applicable period in accordance with the intended method or
methods of distribution by the selling Holders thereof. Notwithstanding anything
to the contrary  contained herein, the Company shall not be required to take any
of the actions  described  in clauses  (i),  (ii) or (iii) above with respect to
each particular  Holder of Registrable  Securities  unless and until the Company
has received  either a written  notice (a  "Registration  Notice") from a Holder
that such Holder  intends to make  offers or sales under the Shelf  Registration
Statement as specified in such  Registration  Notice or a written  response from
such Holder of the type contemplated by Section 2(b);  provided,  however,  that
the Company shall have 7 business days to prepare and file any such amendment or
supplement after receipt of a Registration  Notice.  Once a Holder has delivered
such a written  response or a  Registration  Notice to the Company,  such Holder
shall promptly provide to the Company such information as the Company reasonably
requests in order to identify  such Holder and the method of  distribution  in a
post-effective  amendment to the Shelf Registration Statement or a supplement to
a Prospectus.  Unless  otherwise  approved in writing by the Company in its sole
discretion,  offers or sales under the Shelf Registration  Statement may be made
only during a Sale Period.  Such Holder also shall notify the Company in writing
upon  completion  of such offer or sale or at such time as such Holder no longer
intends to make offers or sales under the Shelf Registration Statement.

                  (c) furnish to each Holder of Registrable  Securities that has
delivered a Registration  Notice to the Company,  without charge, as many copies
of each applicable Prospectus,  including each preliminary  Prospectus,  and any

                                       4

<PAGE>


amendment  or  supplement  thereto and such other  documents  as such Holder may
reasonably  request, in order to facilitate the public sale or other disposition
of  the  Registrable  Securities;  the  Company  consents  to the  use  of  such
Prospectus,  including  each  preliminary  Prospectus,  by each  such  Holder of
Registrable  Securities  in  connection  with  the  offering  and  sale  of  the
Registrable Securities covered by such Prospectus or the preliminary Prospectus.

                  (d) use its reasonable best efforts to register or qualify the
Registrable  Securities by the time the Shelf Registration Statement is declared
effective by the SEC under all applicable state securities or "blue sky" laws of
such jurisdictions as any Holder of Registrable  Securities covered by the Shelf
Registration  Statement  shall  reasonably  request in  writing,  keep each such
registration or qualification effective during the period the Shelf Registration
Statement is required to be kept  effective or during the period offers or sales
are being  made by a Holder  that has  delivered  a  Registration  Notice to the
Company,  whichever is shorter,  and do any and all other acts and things may be
reasonably  necessary  or  advisable  to enable  such Holder to  consummate  the
disposition in each such  jurisdiction of such  Registrable  Securities owned by
such Holder, provided,  however, that the Company not be required (i) to qualify
generally  to do  business  in any  jurisdiction  or to  register as a broker or
dealer in such  jurisdiction  where it would not be  required  so to  qualify or
register but for this Section  3(d),  (ii) to subject  itself to taxation in any
such  jurisdiction  or (iii) to submit to the general  service of process in any
such jurisdiction.

                  (e) notify each Holder when the shelf  Registration  Statement
has become  effective and notify each Holder that has  delivered a  Registration
Notice to the Company  promptly  and, if requested by such Holder,  confirm such
advice in writing (i) when any post-effective  amendments and supplements to the
Shelf  Registration  Statement  become  effective,  (ii) of the  issuance by the
Commission or any state  securities  authority of any stop order  suspending the
effectiveness  of the Shelf  Registration  Statement  or the  initiation  of any
proceedings  for that purpose,  (iii) if the Company  receives any  notification
with  respect  to  the  suspension  of  the  qualification  of  the  Registrable
Securities for sale in any  jurisdiction or the initiation of any proceeding for
such purpose and (iv) of the  happening of any event during the period the Shelf
Registration  Statement is effective as a result of which the Shelf Registration
Statement or a related  Prospectus  contains any untrue  statement of a material
fact or omits to state  any  material  fact  required  to be stated  therein  or
necessary  to make the  statements  therein (in the case of the  Prospectus,  in
light of the circumstances under which they were made) not misleading.

                  (f) make every  reasonable  effort to obtain the withdrawal of
any order suspending the  effectiveness of the Shelf  Registration  Statement at
the carried possible moment.

                  (g) furnish to each Holder that has  delivered a  Registration
Notice to the Company,  without charge, at least one conformed copy of the Shelf
Registration  Statement  and  any  post-effective   amendment  thereto  (without
documents  incorporated  therein  by  reference  or  exhibits  thereto,   unless
requested).

                  (h)  cooperate  with the  selling  Holders to  facilitate  the
timely  preparation  and  delivery  of  certificates   representing  Registrable
Securities  to be sold and not bearing  any  Securities  Act legend;  and enable
certificates  for such  Registrable  Securities to be issued for such numbers of

                                       5

<PAGE>


shares  and  registered  in such names as the  selling  Holders  may  reasonably
request at least two business days prior to any sale of Registrable Securities.

                  (i)  subject  to the last  three  sentences  of  Section  3(b)
hereof,  upon the  occurrence  of any event  contemplated  by  Section  3(e)(iv)
hereof,  use  its  reasonable  best  efforts  promptly  to  prepare  and  file a
supplement  or  prepare,  file  and  obtain  effectiveness  of a  post-effective
amendment to the Shelf  Registration  Statement or a related  Prospectus  or any
document  incorporated  therein by reference or file any other required document
so  that,  as  thereafter   delivered  to  the  purchasers  of  the  Registrable
Securities,  such Prospectus will not contain any untrue statement of a material
fact or omit to state a material fact required to be stated therein or necessary
to make the statements  therein,  in the light of the circumstances  under which
they were made, not misleading.

                  (j) make  available for inspection by  representatives  of the
selling  Holders and any counsel or  accountant  retained by such  Holders,  all
financial and other records, pertinent corporate documents and properties of the
Company,  and cause the  respective  officers,  directors  and  employees of the
Company   to  supply  all   information   reasonably   requested   by  any  such
representative,  counsel or accountant in connection with the Shelf Registration
Statement;  provided, however, that such records, documents or information which
the  Company  determines  in good faith to be  confidential  and  notifies  such
representatives,  counsel or accountants in writing that such records, documents
or information are confidential,  shall not be disclosed by the representatives,
counsel or accountants  unless (i) the disclosure of such records,  documents or
information is necessary to avoid or correct a material misstatement or omission
in the Shelf Registration Statement, (ii) the release of such records, documents
or information is ordered  pursuant to a subpoena or outer order from a court of
competent jurisdiction or (iii) such records, documents or information have been
generally  made  available  to the public  otherwise  than in  violation of this
Agreement.

                  (k)  within  a  reasonable  time  prior to the  filing  of any
Prospectus,  any amendment to the Shelf  Registration  Statement or amendment or
supplement to a Prospectus,  provide  copies of such document (not including any
documents  incorporated by reference therein unless requested) to the Holders of
Registrable Securities that have provided a Registration Notice to the Company.

                  (l) use its reasonable  best efforts to cause all  Registrable
Securities to be listed on any securities  exchange on which similar  securities
issued by the Company are then listed.

                  (m) obtain a CUSIP number for all Registrable Securities,  not
later than the effective date of the Shelf Registration Statement.

                  (n)  otherwise use its  reasonable  efforts to comply with all
applicable  rules and  regulations  of the  Commission and make available to its
security  holders,  as soon as  reasonably  practicable,  an earnings  statement
covering at least 12 months which shall satisfy the  provisions of Section 11(a)
of the Securities Act and Rule 158 thereunder.

                  (o) use its reasonable  best efforts to cause the  Registrable
Securities covered by the Shelf Registration  Statement to be registered with or
approved by such other governmental  agencies or authorities as may be necessary
by virtue of the business and  operations of the Company to enable  Holders that

                                       6

<PAGE>


have delivered Registration Notices to the Company to consummate the disposition
of such Registrable Securities.

                  The Company may require  each Holder to furnish to the Company
in writing such information  regarding the proposed  distribution by such Holder
of such  Registrable  Securities as the Company may from time to time reasonably
request in writing.

                  In  connection  with  and  as a  condition  to  the  Company's
obligations with respect to the Shelf Registration Statement pursuant to Section
2 hereof and this  Section 3, each  Holder  agrees that (i) it will not offer or
sell its Registrable Securities under the Shelf Registration Statement until (A)
it has either (1) provided a Registration Notice pursuant to Section 3(b) hereof
or (2) had Registrable  Securities included in the Shelf Registration  Statement
at the time it became  effective  pursuant to Section 2(b) hereof and (B) it has
received  copies of the  supplemented  or  amended  Prospectus  contemplated  by
Section  3(b)  hereof  and  receives  notice  that any  required  post-effective
amendment has become effective; (ii) upon receipt of any notice from the Company
of the happening of any event of the kind described in Section  3(e)(iv) hereof,
such Holder will forthwith  discontinue  disposition  of Registrable  Securities
pursuant to the Shelf  Registration  Statement until such Holder receives copies
of the  supplemented or amended  Prospectus  contemplated by Section 3(i) hereof
and receives notice that any post-effective amendment has become effective, and,
if so directed by the  Company,  such Holder will deliver to the Company (at the
expense of the Company) all copies in its possession,  other than permanent file
copies  then  in such  Holder's  possession,  of the  Prospectus  covering  such
registrable  Securities current at the time of receipt of such notice; and (iii)
all offers and sales under the Shelf  Registration  Statement shall be completed
during the first available Sale Period when offers or sales can be made pursuant
to clause (i) above, and upon expiration of such Sale Period the Holder will not
offer or sell its Registrable  Securities under the Shelf Registration Statement
until it has again  complied with the  provisions  of clauses  (i)(A)(1) and (B)
above,  provided,  however,  that if the  entirety  of a Sale  Period is for any
reason not  available  to the Holder,  the Holder shall also be entitled to make
offers and sales during the next succeeding Sale Period.


         Section 4.         PIGGYBACK REGISTRATION.

                  (a) Whenever  (x) the Company  proposes to register any shares
of  its  Common  Stock  (or  securities  convertible  into  or  exchangeable  or
exercisable  for such Common Stock) under the Securities Act for its own account
or the account of any shareholder of the Company (other than offerings  pursuant
to  employee  plans,  or  non-cash  offerings  in  connection  with  a  proposed
acquisition,  exchange offer, recapitalization or similar transaction),  and (y)
the  registration  form  otherwise to be used by the Company may be used for the
registration of Registrable Securities (a "Piggyback Registration"), the Company
will give prompt written notice to all Holders of its intention to effect such a
registration and will, subject to Section 4(b) and Section 10 hereof, include in
such registration all Registrable  Securities with respect to which such Holders
request  in writing to be so  included  within 20 days after the  receipt of the
Company's notice.

                  (b) If a  registration  pursuant to this Section 4 involves an
underwritten  offering and the managing  underwriter advises the Company in good
faith that in its opinion the number of  securities  requested to be included in
such registration  exceeds the number which can be sold in such offering without
having an adverse  effect on such  offering,  including  the price at which such

                                       7

<PAGE>


securities  can be sold,  then the  Company  will be required to include in such
registration the maximum number of shares that such  underwriter  advises can be
so sold,  allocated (x) first,  to the securities the Company  proposes to sell,
(y) second,  among the shares of Common  Stock  requested to be included in such
registration by the Holders,  considered in the aggregate (if such  registration
was initiated by the  Company),  and any other  shareholder  of the Company with
shares of Common Stock eligible for registration,  pro rata, on the basis of the
number of shares of Common  Stock  such  holder  requests  be  included  in such
registration,  and (z) third,  among other  securities,  if any,  requested  and
otherwise eligible to be included in such registration.

                  (c) Nothing  contained  herein shall prohibit the Company from
determining,  at any time, not to file a registration statement or, if filed, to
withdraw  such  registration  or terminate or abandon the  registration  related
thereto.


         Section 5.         REQUESTED REGISTRATION.

                  (a) Right to Request Registration. Upon the written request of
Holders owning 10% or more of the outstanding  Registrable Securities then owned
in the aggregate by such Holders (the "Requesting  Holders') (computed for these
purposes  as if all  outstanding  shares of  Preferred  Stock and all  shares of
Preferred Stock thereafter issuable pursuant to the Development  Agreements have
been converted into shares of Common Stock),  requesting that the Company effect
the registration  under the Securities Act of at least the Minimum  Registration
Amount,  the Company shall use its best efforts to effect,  as  expeditiously as
possible, following the prompt (but in no event later than 15 days following the
receipt  of such  written  request)  delivery  of  notice  to all  Holders,  the
registration  under the  Securities  Act of such number of shares of Registrable
Securities  owned by the  Requesting  Holders and  requested  by the  Requesting
Holders to be so registered (subject to Section 5(c) hereof),  together with (x)
all other shares of Common Stock entitled to registration, and (y) securities of
the Company which the Company  elects to register and offer for its own account,
provided,  however,  that the  Company  shall not be  required to (i) subject to
Section  5(b)  below,  effect  more  than a total  of three  such  registrations
pursuant to this Agreement or (ii) file a registration  statement  relating to a
registration  request  pursuant  hereto  within a period of six months after the
effective  date of any other  registration  statement  of the Company  requested
hereunder (other than pursuant to Section 2) or pursuant to which the Requesting
Holders shall have been given an opportunity to participate  pursuant to Section
4 hereof and which  opportunity  they declined or which  registration  statement
under Section 4 hereof  included  shares of  Registrable  Securities (so long as
such  registration  statement  became and was effective for  sufficient  time to
permit the sales  contemplated  thereby);  provided,  further,  that the Company
shall not be required to file a registration  statement  relating to an offering
of Common Stock on a delayed or  continuous  basis  pursuant to Rule 415 (or any
successor to similar effect) promulgated under the Securities Act if the Company
is not, at the time, eligible to register shares of Common Stock on form S-3 (or
a successor form).


         Notwithstanding the foregoing, if the Board of Directors of the Company
determines in its good faith judgment,  (x) after consultation with a nationally
recognized  investment  banking firm,  that there will be an adverse effect on a
then  contemplated  public  offering of the Company's  securities,  (y) that the
disclosures  that would be required to be made by the Company in connection with

                                       8

<PAGE>


such  registration  would  be  materially  harmful  to the  Company  because  of
transactions  then being  considered  by, or other  events then  concerning  the
Company,  or (z) the registration at the time would require the inclusion of pro
forma or other information,  which requirements the Company is reasonably unable
to comply with, then the Company may defer the filing (but not the  preparation)
of the  registration  statement  which is  required  to effect any  registration
pursuant to this Section 5 for a reasonable period of time, but not in excess of
90 calendar days (or any longer period agreed to by the Holders),  provided that
at all times the Company is in good faith using all  reasonable  efforts to file
such registration statement as soon as practicable.

                  (b) Effective Registration.  A registration requested pursuant
to this Section 5 shall not be deemed to have been effected (and, therefore, not
requested  for  purposes  of Section  5(a)  above)  (w) unless the  registration
statement relating thereto has become effective under the Securities Act, (x) if
after it has become  effective such  registration is interfered with by any stop
order,  injunction  or other order or  requirement  of the  Commission  or other
governmental agency or court for any reason other than a misrepresentation or an
omission  by a Holder  and,  as a result  thereof,  the  shares  of  Registrable
Securities  requested  to be  registered  cannot be  completely  distributed  in
accordance  with the plan of  distribution,  (y) if the  conditions  to  closing
specified in the purchase  agreement or underwriting  agreement  entered into in
connection  with such  registration  are not  satisfied  or waived other than by
reason of some act or omission by a participating  Holder or (z) if with respect
to what would otherwise be deemed the third, or last, request under Section 5(a)
hereof,  less than all of the shares of Common Stock that the Holders  requested
be  registered  were  actually  registered  due to the operation of Section 5(c)
hereof,  provided that clause (z) above may not be invoked by the Holders unless
(I) such request includes at least the Minimum  Registrable  Amount,  or (II) if
such  request  includes  an  amount  that is less than the  Minimum  Registrable
Amount,  Rule 144 under the  Securities  Act is not available to the Holders for
the sale in any  three (3) month  period  of all of the  shares of Common  Stock
owned by the Holders;  and provided further that clause (z) above may be invoked
only at the request of Holders  meeting the  foregoing  requirements  and owning
more than 10% of the shares of Registrable  Securities  then owned  (computed as
aforesaid) in the aggregate by the Holders.

                  (c)  Priority.  If a requested  registration  pursuant to this
Section 5 involves an underwritten  offering and the managing  underwriter shall
advise the Company that in its opinion the number of securities  requested to be
included  in such  registration  exceeds  the  number  which can be sold in such
offering without having an adverse effect on such offering,  including the price
at which such  securities  can be sold,  then the  Company  will be  required to
include in such  registration the maximum number of shares that such underwriter
advises can be so sold,  allocated  (x) first,  among all shares of Common Stock
requested by Holders to be included in such registration,  pro rata on the basis
of the number of shares of Common  Stock then owned by each of them (or, if such
holder  requests  that less than all of the shares of Common Stock owned by such
holder be  included  in such  registration  such  lesser  number of shares)  (y)
second,  to any securities  requested to be included in such registration by any
other  shareholder of the Company having  registration  rights and (z) third, to
any securities the Company proposes to sell.


                                      9
<PAGE>


         Section 6.         REGISTRATION PROCEDURES.

         If and  whenever  the Company is  required  to use its best  efforts to
effect  or cause  the  registration  of any  Registrable  Securities  under  the
Securities Act as provided in this Agreement  pursuant to Section 4 or 5 hereof,
the Company shall:

                  (a) prepare and file with the Commission as  expeditiously  as
possible  but in no event  later  than 90 days after  receipt  of a request  for
registration with respect to such Registrable  Shares, a registration  statement
on any form for  which the  Company  then  qualifies  or which  counsel  for the
Company  shall deem  appropriate,  which form shall be available for the sale of
the  Registrable   Securities  in  accordance  with  the  intended   methods  of
distribution  thereof,  and use its  best  efforts  to cause  such  registration
statement to become effective; provided that before filing with the Commission a
registration  statement or prospectus or any amendments or supplements  thereto,
including  documents  incorporated  by reference after the initial filing of any
registration  statement,  the Company  shall (x)  furnish to each  participating
Holder and to one firm of attorneys  selected  collectively by the participating
Holders  and the  holders  of  other  securities  covered  by such  registration
statement,  but in no event to more than one such  counsel for all such  selling
securityholders,  copies  of all such  documents  proposed  to be  filed,  which
documents shall be subject to the review of the  participating  Holders and such
counsel,  and (y) notify the  participating  Holders of any stop order issued or
threatened by the Commission and take all reasonable actions required to prevent
the entry of such stop order or to remove it if entered;

                  (b) prepare and file with the Commission  such  amendments and
supplements to such registration statement and the prospectus used in connection
therewith as may be necessary to keep such registration  statement effective for
a period of not less than 180 days or such shorter period which shall  terminate
when all Registrable Securities covered by such registration statement have been
sold (but not before the expiration of the 90-day period  referred to in Section
4(3) of the Securities Act and Rule 174 thereunder, or any successor thereto, if
applicable),  and comply with the  provisions of the Securities Act with respect
to the  disposition of all  securities  covered by such  registration  statement
during such period in accordance with the intended methods of disposition by the
sellers thereof set forth in such registration statement;

                  (c) furnish,  without charge, to the participating Holders and
each underwriter,  if any, such number of copies of such registration statement,
each  amendment and  supplement  thereto  (including  one conformed copy to each
participating  Holder and one signed copy to each  managing  underwriter  and in
each case including all exhibits thereto),  and the prospectus  included in such
registration  statement (including each preliminary  prospectus),  in conformity
with the  requirements  of the Securities  Act, and such other  documents as the
participating  Holders  may  reasonably  request  in  order  to  facilitate  the
disposition of the Registrable Securities registered thereunder;

                  (d)  use  its  best   efforts  to  register  or  qualify  such
Registrable  Securities covered by such registration  statement under such other
securities or blue sky laws of such jurisdiction as the  participating  Holders,
and the managing  underwriter,  if any,  reasonably  requests and do any and all
other acts and things which may be  reasonable  necessary or advisable to enable
the  participating  Holders  and  each  underwriter,  if any to  consummate  the
disposition  in  such  jurisdiction  of the  Registrable  Securities  registered
thereunder,  provided  that the  Company  shall not be  required  to (x) qualify

                                       10

<PAGE>


generally  to do business in any  jurisdiction  where it would not  otherwise be
required to quality but for this Section 6(d), (y) subject itself to taxation in
any such  jurisdiction  or (z) consent to general service of process in any such
jurisdiction;

                  (e) immediately notify the managing  underwriter,  if any, and
the  Holders at any time when a  prospectus  relating  thereto is required to be
delivered under the Securities Act, of the happening of any event which comes to
the Company's  attention if as a result of such event the prospectus included in
such registration  statement  contains an untrue statement of a material fact or
omits to state any material fact  required to be stated  therein or necessary to
make the  statements  therein not  misleading,  and the Company  shall  promptly
prepare  and  furnish  to the  participating  Holders  and any  other  holder of
securities covered by such registration statement and prospectus a supplement or
amendment to such  prospectus so that as thereafter  delivered,  such prospectus
shall not contain an untrue  statement  of a material  fact or omit to state any
material fact required to be stated  therein or necessary to make the statements
therein not misleading;  provided,  however.  that if the Company  determines in
good faith that the disclosure  that would be required to be made by the Company
would be materially  harmful to the Company because of  transactions  then being
considered by, or other events then concerning,  the Company, or a supplement or
amendment to such  prospectus  at such time would  require the  inclusion of pro
forma or other  information,  which requirement the Company is reasonably unable
to comply with, then the Company may defer for a reasonable  period of time, not
to exceed 90 days,  furnishing to the participating Holders and any other holder
of securities covered by such registration statement and prospectus a supplement
or  amendment  to such  prospectus,  provided,  further,  that at all  times the
Company is in good faith using all reasonable  efforts to file such amendment as
soon as practicable;

                  (f) use its best  efforts to cause all such  securities  being
registered to be listed on each securities  exchange on which similar securities
issued by the Company are then listed, and enter into such customary  agreements
including a listing. application and indemnification agreement in customary form
(provided  that the  applicable  listing  requirements  are  satisfied),  and to
provide a transfer  agent and register for such  Registrable  Shares  covered by
such   registration   statement  no  later  than  the  effective  date  of  such
registration statement;

                  (g) make available for inspection by any of the  participating
Holders and any holder of securities covered by such registration statement, any
underwriter  participating  in any  distribution  pursuant to such  registration
statement, and any attorney,  accountant or other agent retained by such persons
(collectively, the "Inspectors"), all financial and other records of the Company
and its subsidiaries  (collectively,  'Records'), if any, as shall be reasonably
necessary to enable them to exercise  their due  diligence  responsibility,  and
cause the Company's and its subsidiaries'  officers,  directors and employees to
supply all information and respond to all inquiries  reasonably requested by any
such Inspector in connection with such registration  statement.  Notwithstanding
the  foregoing,  the Company shall have no obligation to disclose any Records to
the  Inspector  in the event the  Company  determines  that such  disclosure  is
reasonably  likely to have an adverse  effect on the Company's  ability to asset
the existence of an attorney-client privilege with respect thereto;

                  (h) if  requested  use its  best  efforts  to  obtain  a "cold
comfort"  letter and a  "bring-down  cold  comfort"  letter  from the  Company's
independent  public  accountants  in customary form and covering such matters of
the type customarily covered by such letters;

                                       11

<PAGE>


                  (i) enter into a form of underwriting  agreement that contains
customary terms and provisions for similar securities offerings;

                  (j) make available senior management  personnel to participate
in. and cause them to cooperate with the  underwriters in connection with. "road
show" and other customary marketing activities,  including "one-on-one" meetings
with prospective purchasers of the Registrable Securities; and

                  (k)  otherwise  use  its  best  efforts  to  comply  with  all
applicable  rules and regulations of the  Commission,  and make available to its
security  holders.  as soon as  reasonably  practicable.  an  earning  statement
covering a period of at least 12 months,  beginning with the first:  month after
the effective date of the  registration  statement (as the term "effective date"
is defined in Rule 158(c) under the  Securities  Act),  which earning  statement
shall satisfy the provisions of Section 11(a) of the Securities Act and Rule 158
thereunder.

         It shall be a condition  precedent to the  obligation of the Company to
take any action pursuant to this Agreement in respect of Registrable  Securities
which are to be  registered at the request of any of the  participating  Holders
that the  participating  Holders shall  furnish to the Company such  information
regarding  the  securities  held by the  participating  Holders and the intended
method of  disposition  thereof as the Company shall  reasonably  request and as
shall be required in correction with the action taken by the Company.

         Each of the Holders  agrees  that,  upon receipt of any notice from the
Company of the  happening  of any event of the kind  described  in Section  6(e)
hereof, the Holders shall discontinue disposition of Registrable Shares pursuant
to the registration statement covering such Registrable Securities until receipt
of the copies of the supplemented or amended prospectus  contemplated by Section
6(c) hereof or until otherwise  notified by the Company,  and, if so directed by
the Company,  the  participating  Holders  shall  deliver to the Company (at the
Company's  expense)  all  copies  (including,  without  limitation,  any and all
drafts),  other than permanent file copies,  then in any participating  Holder's
possession,  of the prospectus coveting such Registrable  Securities at the time
of receipt of such notice.  In the event the Company shall give any such notice,
the period  specified in Section 6(b) hereof shall be extended by the greater of
(x) three months and (y) the number of days during the period from and including
the date of the giving of such  notice  pursuant  to Section  6(e) hereof to and
including  the date when each of the  participating  Holders shall have received
the copies of the  supplemented  or amended  prospectus  contemplated by Section
6(e) hereof.

         Section 7.         SELECTION OF UNDERWRITERS.

         If  any  offering  pursuant  to a  registration  statement  is to be an
underwritten  offering,  the  Company  will  select a  managing  underwriter  or
underwriters  to  administer  the  offering;  provided  that  in the  case  of a
registration  statement  pursuant to Section 5 hereof,  the Holders holding more
than 50% of the  shares of  Registrable  Securities  held by the  Holders  to be
included in such underwritten  offering shall select the managing underwriter or
underwriters,  subject  to  the  consent  of  the  Company  which  shall  not be
unreasonably withheld.

                                       12

<PAGE>

         Section 8.         REGISTRATION EXPENSES.

         The Company shall pay, in connection with any registration  pursuant to
Section 2. 4 or 5, the following  registration  expenses  incurred in connection
therewith:  (i) all Commission,  stock exchange or NASD  registration and filing
fees, (ii) all fees and expenses. of compliance with securities or blue sky laws
(including  reasonable fees and  disbursements of counsel in connection with the
blue sky qualifications of the Registrable Securities), (iii) printing expenses,
(iv) internal expenses (including without limitation,  all salaries and expenses
of its officers and employees  performing legal or accounting  duties),  (v) the
fees and expenses  incurred in  connection  with the listing of the  Registrable
Securities on any national securities exchange or interdealer  quotation system,
(vi) the  reasonable  fees and  disbursements  of counsel  for the  Company  and
customary  fees  and  expenses  for  independent  certified  public  accountants
retained by the Company  (including the expenses of any comfort letters or costs
associated with the delivery by independent  certified  public  accountants of a
comfort letter or comfort letters),  (vii) the reasonable fees and disbursements
of not more than one firm of  attorneys  acting as legal  counsel for (x) all of
the selling shareholders, collectively, in respect of a registration pursuant to
Section  2 hereof  or (y) all of the  participating  Holders,  collectively,  in
respect of a  registration  pursuant to Sections 4 or 5 hereof,  (viii) the fees
and expenses of any registrar and transfer agent for the Common Stock,  (ix) the
underwriting fees, discounts and commissions  applicable to any shares of Common
Stock sold for the account of the Company and (x) all  expenses of any Person in
preparing or assisting in preparing, word processing,  printing and distributing
any  registration  statement,  prospectus,   certificates  and  other  documents
relating to the  performance of and compliance  with this  Agreement.  Except as
otherwise  provided in clause (ix) of this Section 8, the Company  shall have no
obligation to pay any underwriting fees,  discounts or commissions  attributable
to the sale of Registrable Shares.


         Section 9.         INDEMNIFICATION; CONTRIBUTION.

                  (a) The Company  agrees to indemnify  and hold  harmless  each
seller of  Registrable  Securities  covered by a  Registration  Statement  filed
pursuant to this Agreement,  and such seller's  partners,  directors,  officers,
employees  and any Person who  controls  such seller  under the  Securities  Act
(each, an "Indemnitee")  from and against any and all losses,  claims,  damages,
liabilities and expenses (including  reasonable costs of investigation)  arising
out of or based  upon any untrue  statement  or alleged  untrue  statement  of a
material fact contained in any prepricing prospectus,  registration statement or
prospectus or in any amendment or supplement thereto, or arising out of or based
upon any omission or alleged  omission to state therein a material fact required
to be stated therein or necessary to make the statements therein not misleading,
except insofar as such losses, claims, damages, liabilities or expenses rise out
of or are  based  upon any  untrue  statement  or  omission  or  alleged  untrue
statement  or  omission  which has been made  therein  or omitted  therefrom  in
reliance upon and in conformity with the information relating to a participating
Holder  furnished  in writing to the Company by or on behalf of a  participating
Holder  expressly  for use in  connection  therewith.  The  foregoing  indemnity
agreement  shall be in addition to any liability which the Company may otherwise
have.

                  (b) If any action, suit or proceeding shall be brought against
an Indemnitee in respect of which  indemnity may be sought  against the Company,
such Indemnitee shall promptly notify the Company,  and the Company shall assume
the defense thereof, including the employment of counsel and payment of all fees

                                       13

<PAGE>


and expenses.  The Indemnitee shall have the right to employ separate counsel in
any such action,  suit or proceeding and to participate in the defense  thereof,
but the fees and  expenses  of such  counsel  shall  be at the  expense  of such
Indemnitee  unless  (x) the  Company  has agreed in writing to pay such fees and
expenses,  (y) the Company has failed to assume the defense and employ  counsel,
or (z) the named parties to any such action,  suit or proceeding  (including any
impleaded  parties)  include  both such  Indemnitee  and the  Company,  and such
Indemnitee  shall have been advised by its counsel that  representation  of such
Indemnitee  and the Company by the same  counsel  would be  inappropriate  under
applicable standards of professional conduct (whether or not such representation
by the same  counsel has been  proposed)  due to actual or  potential  differing
interests  between  them (in which case the Company  shall not have the right to
assume  the  defense  of such  action,  suit or  proceeding  on  behalf  of such
Indemnitee).  It is understood,  however,  that the Company shall, in connection
with any one such  action,  suit or  proceeding  or separate  but  substantially
similar  or  related  actions,  suits or  proceedings  in the same  jurisdiction
arising out of the same general allegations or circumstances,  be liable for the
reasonable fees and expenses of only one separate firm of attorneys (in addition
to any local counsel) at any time for all such  Indemnitees not having actual or
potential  differing  interests  among  themselves,  and that all such  fees and
expenses  shall be  reimbursed  as they are  incurred.  The Company shall not be
liable  for any  settlement  of any such  action,  suit or  proceeding  effected
without its written  consent,  but if settled with such written  consent,  or if
them  be a  final  judgment  for  the  plaintiff  in any  such  action,  suit or
proceeding,  the Company agrees to indemnify and hold harmless such  Indemnitee,
to the extent  provided in the preceding  paragraph,  from and against any loss,
claim, damage, liability or expense by reason of such settlement or judgment.

                  (c)  Each  of the  participating  Holders,  severally  and not
jointly,  agree to indemnify and hold harmless the Company,  its directors,  its
officers who sign the  registration  statement,  and any person who controls the
Company  within the meaning of Section 15 of the Securities Act or Section 20 of
the Exchange Act, to the same extent as the foregoing indemnity from the Company
to an Indemnitee,  but only with respect to information  relating to such Holder
furnished  in writing by or on behalf of such  Holder  expressly  for use in the
registration  statement,   prospectus  or  any  prepricing  prospectus,  or  any
amendment or supplement  thereto.  If any action,  suit or  proceeding  shall be
brought against the Company, any of its directors, any such officer, or any such
controlling  person  based  on the  registration  statement,  prospectus  or any
prepricing prospectus, or any amendment or supplement thereto, and in respect of
which  indemnity may be sought against any Holder pursuant to this Section 9(c),
such  Holder  shall have the rights and duties  given to the  Company by Section
9(b) hereof  (except that if the Company shall have assumed the defense  thereof
such  Holder  shall not be required  to do so, but may employ  separate  counsel
therein and  participate  in the defense  thereof,  but the fees and expenses of
such counsel shall be at the Holder's expense),  and the Company, its directors,
any such  officer,  and any such  controlling  person  shall have the rights and
duties given to an  Indemnitee by Section 9(b) hereof.  The foregoing  indemnity
agreement shall be in addition to any liability which the participating  Holders
may otherwise have.

                  (d) If the  indemnification  provided for in this Section 9 is
unavailable  to an  indemnified  party  under  paragraphs  (a) or (c)  hereof in
respect of any losses,  claims,  damages,  liabilities  or expenses  referred to
therein,  then an indemnifying  party, in lieu of indemnifying  such indemnified
party,  shall contribute to the amount paid or payable by such indemnified party
as a result of such losses,  claims,  damages,  liabilities  or expenses in such
proportion as is appropriate to reflect the relative fault of the Company and of
the  participating  Holders in connection  with the statements or omissions that

                                       14

<PAGE>


resulted in such losses, claims, damages,  liabilities or expenses. The relative
fault of the  Company  on the one hand and a  participating  Holder on the other
hand shall be determined by reference to, among other things, whether the untrue
or alleged  untrue  statement  of a  material  fact or the  omission  or alleged
- - -omission  to state a material  fact  relates  to  information  supplied  by the
Company  on the one hand or by such  participating  Holder on the other hand and
the parties' relative intent,  knowledge,  access or information and opportunity
to correct or prevent such statement or omission.

                  (e) The Company and the  participating  Holders  agree that it
would not be just and equitable if contribution  pursuant to this Section 9 were
determined by a pro rata  allocation  or by any other method of allocation  that
does not take  account of the  equitable  considerations  referred to in Section
9(d) hereof.  The amount paid or payable by an indemnified  party as a result of
the losses,  claims,  damages,  liabilities and expenses  referred to in Section
9(d) hereof  shall be deemed to include,  subject to the  limitations  set forth
above, any legal or other expenses reasonably incurred by such indemnified party
in connection with investigating any claim or defending any such action, suit or
proceeding.  Notwithstanding  the provisions of this Section 9, no participating
Holder  shall be  required to  contribute  any amount in excess of the amount by
which the  proceeds  to such  participating  Holder  exceeds  the  amount of any
damages which such  participating  Holder has otherwise  been required to pay by
reason of such  untrue or  alleged  untrue  statement  or  omission  or  alleged
omission. No person guilty of fraudulent  misrepresentation  (within the meaning
of Section 11(f) of the Securities Act) shall be entitled to  contribution  from
any person who was not guilty of such fraudulent misrepresentation.

                  (f) No  indemnifying  party shall,  without the prior  written
consent of the  indemnified  party,  effect  any  settlement  of any  pending or
threatened action,  suit or proceeding in respect of which any indemnified party
is or could have been a party and indemnity could have been sought  hereunder by
such indemnified party, unless such settlement includes an-unconditional release
of such  indemnified  party from all  liability  on claims  that are the subject
matter of such action, suit or proceeding.

                  (g) Any losses, claims,  damages,  liabilities or expenses for
which an indemnified parry is entitled to  indemnification or contribution under
this Section 9 shall be paid by the indemnifying  party to the indemnified party
as such losses,  claims,  damages,  liabilities  or expenses are  incurred.  The
indemnity and contribution  agreements  contained in this Section 9 shall remain
operative and in full force and effect, regardless of (i) any investigation made
by or on behalf of an Indemnitee, the Company, its directors or officers, or any
person controlling the Company, and (ii) any termination of this Agreement.


         Section 10.        PARTICIPATION IN UNDERWRITTEN REGISTRATIONS.

         A Holder may not participate in any underwritten  offering  pursuant to
Section 4 or 5 hereof  unless  such  Holder (i)  agrees to sell its  Registrable
Securities on the basis provided in any underwriting  arrangements which, to the
extent  applicable  solely to the  participating  Holders,  are  approved by the
participating  Holders in their  reasonable  discretion or which,  to the extent
applicable  to the Company and the  participating  Holders,  are approved by the
Company  in its  reasonable  discretion  and (ii)  completes  and  executes  all
questionnaires,  powers of attorney,  indemnities,  underwriting  agreements and
other documents  (including lock-up  agreements)  reasonably  required under the

                                       15

<PAGE>


terms of such  underwriting  arrangements  which are not in consistent  with the
terms of this Agreement.



         Section 11.        OTHER REGISTRATION RIGHTS.

         The  Company  agrees that it shall not enter into any  agreement  which
provides  registration  rights  to any  Person  that are  inconsistent  with the
provisions  contained in this  Agreement.  If the Company does become a party to
such an agreement,  the Company agrees that to the extent that the provisions of
such agreement  conflict with this  Agreement,  the provisions of this Agreement
shall control.

         Section 12.        RULE 144 SALES.

                  (a)  The  Company  covenants  that it will  file  the  reports
required to be filed by the Company  under the  Securities  Act and the Exchange
Act, so as to enable any Holder to sell Registrable  Securities pursuant to Rule
144 under the Securities Act.

                  (b) In connection with any sale, transfer or other disposition
by any  Holder  of any  Registrable  Securities  pursuant  to Rule 144 under the
Securities  Act, the Company shall  cooperate with such Holder to facilitate the
timely  preparation  and  delivery  of  certificates   representing  Registrable
Securities  to be sold and not bearing  any  Securities  Act legend,  and enable
certificates for such Registrable Securities to be for such number of shares and
registered in such names as the selling Holders may reasonably  request at least
two business days prior to any sale of Registrable Securities.


         Section 13.        MISCELLANEOUS.

                  (a) Amendments and Waivers.  The provisions of this Agreement,
including  the  provisions  of this  sentence,  may not be amended,  modified or
supplemented,  and waivers or consents to departures from the provisions  hereto
may not be  given  without  the  written  consent  of the  Company  and  Holders
constituting   Majority   Holders;   provided,   however,   that  no  amendment,
modification or supplement or waiver or consent to the departure with respect to
the provisions of Sections 1 through 12, inclusive, hereof or which would impair
the rights of any Holder  under such  provisions,  shall be effective as against
any  Holder.  Notice  of any  amendment,  modification  or  supplement  to  this
Agreement  adopted in  accordance  with this Section  13(a) shall be provided by
Company to each Holder at least thirty (30) days prior to the effective  date of
such amendment, modification or supplement.

                  (b) Notices. All notices and other communications provided for
or permitted  hereunder  shall be made in writing by hand  delivery,  registered
first-class  mail,  telex,  telecopier  or any  courier  guaranteeing  overnight
delivery,  (i) if to a Holder,  at the most current address given by such Holder
to the Company by of a notice given in  accordance  with the  provisions of this
Section  13(b),  which address  initially  is, with respect to each Holder,  the
address  set  forth  in  the  Contribution  Agreement,  the  Asset  Contribution
Agreement or the Development Agreements, or (ii) if to the Company, at One Logan
Square, Suite 1105, Philadelphia, PA 19103.

                                       16

<PAGE>



         All such notices and  communications  shall be deemed to have been duly
given:  at the time  delivered by hand, if personally  delivered;  five business
days after  being  deposited  in the mail,  postage  prepaid,  if  mailed:  when
answered back, if telexed;  when receipt is acknowledged,  if telecopied;  or at
the  time  delivered  if  delivered  by an air  courier  guaranteeing  overnight
delivery.

                  (c) Successors and Assigns.  This Agreement shall inure to the
benefit of and be binding upon the  successors,  assigns and transferees of each
of the Company and the Holders,  including  without  limitation  and without the
need for an express assignment,  subsequent Holders. If any successor,  assignee
or transferee of any Holder shall acquire Registrable Securities, in any manner,
whether by operation of law or otherwise,  such Registrable  Securities shall be
held  subject to all of the terms of this  Agreement,  and by taking and holding
such  Registrable  Securities  such  Person  shall be  entitled  to receive  the
benefits hereof and shall be  conclusively  deemed to have agreed to be bound by
all of the terms and provisions hereof.

                  (d)  Headings.  The  headings  in this  Agreement  are for the
convenience  of  reference  only and  shall not limit or  otherwise  affect  the
meaning hereof.

                  (e)  GOVERNING  LAW. THIS  AGREEMENT  SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE  WITH THE LAWS OF THE STATE OF DELAWARE  WITHOUT  GIVING
EFFECT TO THE CONFLICTS OF LAW PROVISIONS THEREOF.

                  (f)  Specific   Performance.   The  Company  and  the  Holders
acknowledge  that there would be no adequate remedy at law if any party fails to
perform any of its obligations hereunder, and accordingly agree that the Company
and each Holder,  in addition to any other remedy to which it may be entitled at
law or in  equity,  shall be  entitled  to compel  specific  performance  of the
obligations  of another under this  Agreement in  accordance  with the terms and
conditions  of this  Agreement  in any court of the  United  States or any State
thereof having jurisdiction.

                  (g)  Entire  Agreement.  This  Agreement  is  intended  by the
Company as a final  expression of its agreement and is intended to be a complete
and exclusive  statement of the agreement  and  understanding  of the Company in
respect of the subject matter contained  herein.  This Agreement  supersedes all
prior agreements and  understandings of the Company with respect to such subject
matter.

                  (h)  Notwithstanding  any other provision of this Agreement to
the contrary,  the total number of days that the Holders shall be precluded from
the  disposition  of  Registrable  Securities  under an  effective  Registration
Statement  coupled  with the total number of days that the Company may defer the
filing of the  registration  statement  hereunder  shall not  exceed  180 in any
12-month period during the first two years from the date of this Agreement,  and
shall not exceed 120 days in any 12-month period thereafter.

                                       17

<PAGE>


         IN WITNESS  WHEREOF,  the Company has executed this Agreement as of the
date first written above.

                                        CORPORATE OFFICE PROPERTIES TRUST


                                         By:   /s/ Clay W. Hamlin, III
                                                  Clay W. Hamlin, III
                                          President and Chief Executive Officer



                                       18





                             ARTICLES SUPPLEMENTARY
                                       OF
                        CORPORATE OFFICE PROPERTIES TRUST
                      SERIES A CONVERTIBLE PREFERRED SHARES


                                   ARTICLE ONE

         CORPORATE OFFICE PROPERTIES TRUST (the "Trust"), pursuant to the
provisions of Section 8-203(b) of Title 8 of the Corporations and Associations
Article of the Annotated Code of Maryland, as amended (the "Maryland REIT Law"),
hereby files these Articles Supplementary classifying its Series A Convertible
Preferred Shares of Beneficial Interest of the Trust (the "Articles") prior to
the issuance of any shares of Series A Convertible Preferred Shares of
Beneficial Interest, such series of unissued shares having been established by a
resolution duly adopted by all necessary action on the part of the Trust and the
Board of Trustees of the Trust (the "Board of Trustees"), as provided for in the
Amended and Restated Declaration of Trust, as amended (the "Declaration of
Trust").

                                   ARTICLE TWO

         The name of the Trust is Corporate Office Properties Trust.

                                  ARTICLE THREE

         Pursuant to the authority conferred upon the Board of Trustees by the
Declaration of Trust and Section 8-203(a)(6) of the Maryland REIT Law, the Board
of Trustees adopted a resolution establishing the Series A Convertible Preferred
Shares of Beneficial Interest of the Trust and designating the series and fixing
and determining the preferences, limitations, and relative rights thereof, as
set forth in the true and correct copy of the resolution attached hereto as
Exhibit A (the "Designating Resolution").

                                  ARTICLE FOUR

         The Designating Resolution was adopted effective as of September 28,
1998.

                                  ARTICLE FIVE

         The Designating Resolution has been duly adopted by all necessary
action on the part of the Trust.


<PAGE>



                                                         2

         IN WITNESS WHEREOF, the undersigned officer has executed these Articles
effective as of September 28, 1998.

                                            CORPORATE OFFICE PROPERTIES TRUST

                                            By:  /s/ Clay W. Hamlin, III
                                                    Clay W. Hamlin, III
                                           President and Chief Executive Officer


Attest:


   /s/ Denise Liszewski
Name:    Denise Liszewski
Title:   Assistant Secretary

                                       2

<PAGE>




                                    EXHIBIT A

                             DESIGNATING RESOLUTION
                                BOARD OF TRUSTEES
                        CORPORATE OFFICE PROPERTIES TRUST
                               September 28, 1998


             AUTHORIZATION OF SERIES A CONVERTIBLE PREFERRED SHARES
                             OF BENEFICIAL INTEREST

         WHEREAS, the Board of Trustees of Corporate Office Properties Trust
(the "Trust") has deemed it to be in the best interest of the Trust and its
shareholders for the Trust to establish a series of preferred shares pursuant to
the authority granted to the Board of Trustees in the Amended and Restated
Declaration of Trust, as amended (the "Declaration of Trust"), of the Trust:

         NOW, THEREFORE, BE IT RESOLVED, that, pursuant to the authority vested
in the Board of Trustees by the Declaration of Trust, a series of preferred
shares is hereby established, and the terms of the same shall be as follows:

         Section 1. Number of Shares and Designation. This series of Preferred
Shares of Beneficial Interest shall be designated as Series A Convertible
Preferred Shares of Beneficial Interest, $.01 par value per share (the "Series A
Preferred Shares") and up to 1,025,000 shall be the number of such Preferred
Shares of Beneficial Interest constituting such series.

         Section 2.        Definitions.  For purposes of the Series A Preferred
Shares, the following terms shall have the meanings indicated:

         "Affiliate" shall mean, with respect to a particular Person, any other
         Person controlling, controlled by or under common control with such
         particular Person, including any directors and majority-owned entities
         of that Person and of its other Affiliates.

         "Change of Control" shall mean (i) a sale or other transfer of more
         than 50% of the then outstanding Common Shares to an Unrelated Third
         Party or its Affiliates, (ii) a merger or consolidation of the Trust
         with an Unrelated Third Party where the Trust is not the surviving
         entity, (iii) the sale of all or substantially all of the assets of the
         Trust or (iv) the voluntary or involuntary liquidation, dissolution and
         winding up of the Trust.

         "Common Shares" shall mean Common Shares of Beneficial Interest, $.01
         par value per share, of the Trust or such shares of the Trust's capital
         shares into which such Common Shares of Beneficial Interest shall be
         reclassified.



<PAGE>


         "Common Share Dilution Price" shall have the meaning set forth in
         Section 8(c).

         "Constellation" shall mean Constellation Real Estate Group, Inc. or any
         of its Affiliates.

         "Conversion Rate" shall mean 1.8748 Common Shares for each Series A
         Preferred Share, subject to adjustment as provided in paragraph (f) of
         Section 6 hereof.

         "Current Market Price" of publicly traded Common Shares or any other
         class or series of capital shares or other security of the Trust or of
         any similar security of any other issuer for any day shall mean the
         last reported sales price, regular way settlement on such day, or, if
         no sale takes place on such day, the average of the reported closing
         bid and asked prices regular way on such day, in either case as
         reported on the New York Stock Exchange ("NYSE") or, if such security
         is not listed or admitted for trading on the NYSE, on the principal
         national securities exchange on which such security is listed or
         admitted for trading or, if not listed or admitted for trading on any
         national securities exchange, on the National Market of the National
         Association of Securities Dealers, Inc. Automated Quotations System
         ("NASDAQ") or, if such security is not quoted on such National Market,
         the average of the closing bid and asked prices on such day in the
         over-the-counter market as reported by NASDAQ or, if bid and asked
         prices for such security on such day shall not have been reported
         through NASDAQ, the average of the bid and asked prices on such day as
         furnished by any NYSE member firm regularly making a market in such
         security selected for such purpose by the Chief Executive Officer or
         the Trustees or if any class or series of securities are not publicly
         traded, the fair value of the shares of such class as determined
         reasonably and in good faith by the Trustees.

         "Declaration of Trust" shall have the meaning set forth in the
         Preamble.

         "Dilutive Transaction" shall have the meaning set forth in Section
         8(c).

         "Junior Shares" shall mean the Common Shares and any other class or
         series of capital shares of the Trust over which the Series A Preferred
         Shares have preference or priority in the payment of dividends or in
         the distribution of assets on any liquidation, dissolution or winding
         up of the Trust.

         "Person" shall mean any individual, firm, partnership, corporation or
         other entity and shall include any successor (by merger or otherwise)
         of such entity.

         "Series A Preferred Shares" shall have the meaning set forth in Section
         1 hereof.

         "Standstill Period" shall mean the period ending on the earliest of (i)
         September 28, 2000, (ii) five business days prior to the effective date
         of any Change of Control or (iii) a date established by resolution of
         the Board of Trustees.

                                       2

<PAGE>


         "Tendered Non-Converted Shares" shall have the meaning set forth in
         Section 6(a).

         "Trading Day", as to any Common Shares, shall mean any day on which
         such Common Shares are traded on the NYSE or, if such Common Shares are
         not listed or admitted for trading on the NYSE, on the principal
         national securities exchange on which such Common Shares are listed or
         admitted or, if such Common Shares are not listed or admitted for
         trading on any national securities exchange, on the National Market of
         NASDAQ or, if such Common Shares are not quoted on such National
         Market, in the Common Shares market in which such Common Shares are
         traded.

         "Transaction" shall  have  the meaning  set  forth in  paragraph (d) of
         Section 6 hereof.

         "Transfer Agent" means Norwest Banks (or its Affiliates) or any U.S.
         bank with aggregate capital, surplus and undivided profits, as shown on
         its last published report, of at least $30,000,000 as may be designated
         by the Trustees or their designee as the transfer agent for the Series
         A Preferred Shares.

         "Trust" shall have the meaning set forth in the Preamble.

         "Trustees" shall mean the Trustees of the Trust or any committee
         authorized by such Trustees to perform any of its responsibilities with
         respect to the Series A Preferred Shares.

         "Unrelated Third Party" shall mean a Person other than the Trust or any
         Affiliate of the Trust and other than Constellation.

         "45% Ceiling Requirement" shall have the meaning  set  forth in Section
         6(a).

         Section 3. Dividends. Except as provided in paragraph (a) of Section 6,
the holders of each Series A Preferred Share shall be entitled to receive
cumulative dividends and distributions payable from the date of issuance of such
Series A Preferred Stock quarterly and in preference and priority to the
dividends and distributions payable on each Junior Share, when, as and if
declared by the Board of Trustees of the Trust out of funds legally available
therefor, at the annual rate of $1.375 per share. Cumulative dividends will
accrue whether or not there are profits, surplus or other funds of the Trust
legally available for payment of dividends. The record and payment dates for the
Common Shares, if any, shall be the same as the record and payment dates for the
Series A Preferred Shares. If such cumulative dividends in respect of any prior
or current quarterly dividend period shall not have been declared and paid or if
there shall not have been a sum sufficient for the payment thereof set apart,
the deficiency shall first be fully paid before (i) any dividend or other
distribution (other than dividends payable in Common Shares) shall be paid or
declared and set apart with respect to the Junior Shares or (ii) any Junior
Shares shall be repurchased or redeemed by the Trust. Dividends shall be payable
pro rata for partial quarterly periods. In the event that any Series A Preferred
Share is converted into Common

                                       3

 
<PAGE>


Shares pursuant to Section 6 below, holders of
Series A Preferred Shares whose conversion is deemed effective before the close
of business on a dividend payment record date will not be entitled to receive
any portion of the dividend payable on such Series A Preferred Shares on the
corresponding dividend payment date for the current quarter to which that record
date pertains but will, however, be entitled to receive the entire dividend for
such quarterly period payable, if any, on the Common Shares issuable upon
conversion provided that any conversion of Series A Preferred Shares becomes
effective prior to the close of business on the record date for such dividend
payable on such Common Shares. A holder of Series A Preferred Shares on a
dividend payment record date who (or whose transferee) tenders such shares for
conversion into Common Shares after such dividend payment record date will be
entitled to receive the dividend payable on such Series A Preferred Shares on
the corresponding dividend payment date. Except as provided above, the Trust
will pay at the time of conversion all accrued and unpaid dividends, whether or
not declared, on converted Series A Preferred Shares.

         Section 4.        Liquidation Preference.

         (a) In the event of any liquidation, dissolution or winding up of the
Trust, whether voluntary or involuntary, before any payment or distribution of
the assets of the Trust (whether capital or surplus) shall be made to or set
apart for the holders of Junior Shares, the holders of Series A Preferred Shares
shall be entitled to receive $25.00 per Series A Preferred Share plus an amount
equal to all accrued and unpaid dividends thereon to the date fixed for
distribution whether or not declared; but such holders shall not be entitled to
any further payment. Until the holders of the Series A Preferred Shares have
been paid the liquidation preference in full, no payment will be made to any
holder of Junior Shares upon the liquidation, dissolution or winding up of the
Trust. If, upon any liquidation, dissolution or winding up of the Trust, the
assets of the Trust, or proceeds thereof, distributable among the holders of
Series A Preferred Shares shall be insufficient to pay in full the preferential
amount aforesaid, then such assets, or the proceeds thereof, shall be
distributed among the holders of Series A Preferred Shares ratably in the same
proportion as the respective amounts that would be payable on such Series A
Preferred Shares if all amounts payable thereon were paid in full. For the
purposes of this Section 4, (i) a consolidation or merger of the Trust with one
or more corporations or (ii) a statutory share exchange shall not be deemed to
be a liquidation, dissolution or winding up, voluntary or involuntary, of the
Trust. A sale or transfer of all or substantially all of the Trust's assets
shall be deemed to be a liquidation, dissolution or winding up of the Trust.

         (b) Upon any liquidation, dissolution or winding up of the Trust, after
payment shall have been made in full to the holders of Series A Preferred
Shares, as provided in this Section 4, any other series or class or classes of
Junior Shares shall, subject to the respective terms thereof, be entitled to
receive any and all assets remaining to be paid or distributed, and the holders
of the Series A Preferred Shares shall not be entitled to share therein.

         Section 5. Shares To Be Retired. All Series A Preferred Shares which
shall have been issued and reacquired in any manner by the Trust shall be
restored to the status of

                                       4

 <PAGE>


authorized, but unissued Preferred Shares, without
designation as to series. The Trust may also retire any unissued Series A
Preferred Shares, and such shares shall then be restored to the status of
authorized but unissued Preferred Shares, without designation as to series.

         Section 6.        Conversion.

         Holders of Series A Preferred Shares shall have the right to convert
all or a portion of such shares into Common Shares, as follows:

         (a) Subject to and upon compliance with the provisions of this Section
6, a holder of Series A Preferred Shares shall have the right, at such holder's
option, at any time after the end of the Standstill Period to convert such
shares, in whole or in part, into the number of fully paid and nonassessable
shares of authorized but previously unissued Common Shares obtained by
multiplying the Conversion Rate by the number of Series A Preferred Shares to be
converted by surrendering such shares to be converted, such surrender to be made
in the manner provided in paragraph (b) of this Section 6; provided, however,
that no holder of such shares shall convert such shares if such holder and its
Affiliates would hold after such conversion 45% or more of the outstanding
Common Shares (the "45% Ceiling Requirement"). If such conversion would exceed
the 45% Ceiling Requirement, then upon surrendering the Series A Preferred Share
certificates pertaining to such excess Common Shares as provided in paragraph
(b) of this Section 6, the holder shall continue to be a holder of Series A
Preferred Shares (the "Tendered Non-Converted Shares") pertaining to such excess
Common Shares except that, in lieu of the dividends otherwise payable on such
Tendered Non-Converted Shares (but not in lieu of accrued and unpaid dividends
applicable to quarterly periods prior to such delivery) the holder of Tendered
Non-Converted Shares shall receive the dividends on the Common Shares into which
such Tendered Non-Converted Shares would have been convertible but for the 45%
Ceiling Requirement, and such Tendered Non-Converted Shares shall convert
thereafter to Common Shares without further action by such holder as of the last
day of each calendar quarter to the extent then permitted by the 45% Ceiling
Requirement.

         (b) In order to exercise the conversion right, the holder of each
Series A Preferred Share to be converted shall surrender the certificate
representing such shares, duly endorsed or assigned to the Trust or in blank, at
the office of the Transfer Agent, accompanied by written notice to the Trust
that the holder thereof elects to convert such Series A Preferred Shares. Unless
the shares issuable on conversion are to be issued in the same name as the name
in which such Series A Preferred Shares are registered, each share surrendered
for conversion shall be accompanied by instruments of transfer, in form
reasonably satisfactory to the Trust, duly executed by the holder or such
holder's duly authorized attorney and an amount sufficient to pay any transfer
or similar tax (or evidence reasonably satisfactory to the Trust demonstrating
that such taxes have been paid) as required by paragraph (j) of this Section 6.
As promptly as practicable after the surrender of certificates for Series A
Preferred Shares as aforesaid, the Trust shall issue and shall deliver at such
office to such holder, or send on such holder's written order, a certificate or
certificates for the number of full Common Shares issuable upon the conversion




                                       5
<PAGE>


of such Series A Preferred Shares in accordance with provisions of this Section
6, and any fractional interest in respect of a Common Share arising upon such
conversion shall be settled as provided in paragraph (c) of this Section 6. If
all Series A Preferred Shares evidenced by any certificate are not converted,
the Trust shall issue and deliver at such office to such holder a certificate
for the remaining Series A Preferred Shares not converted. Each conversion shall
be deemed to have been effected immediately prior to the close of business on
the date on which the certificates for Series A Preferred Shares shall have been
surrendered and such notice received by the Trust as aforesaid, and the Person
or Persons in whose name or names any certificate or certificates for Common
Shares shall be issuable upon such conversion shall be deemed to have become the
holder or holders of record of the shares represented thereby at such time on
such date unless the share transfer books of the Trust shall be closed on that
date, in which event such Person or Persons shall be deemed to have become such
holder or holders of record at the close of business on the next succeeding day
on which such transfer books are open, provided that such closure of the share
transfer books shall not delay the date on which such Person shall become a
holder of such shares by more than two business days.

         (c) No fractional Common Share or scrip representing fractions of a
Common Share shall be issued upon conversion of the Series A Preferred Shares.
Instead of any fractional interest in a Common Share that would otherwise be
deliverable upon the conversion of Series A Preferred Shares, the Trust shall
pay to the holder of such share an amount in cash based upon the Current Market
Price of the Common Shares on the Trading Day immediately preceding the date of
conversion. If more than one share shall be surrendered for conversion at one
time by the same holder, the number of full Common Shares issuable upon
conversion thereof shall be computed on the basis of the aggregate number of
Series A Preferred Shares so surrendered.

         (d) If the Trust shall be a party to any transaction (including without
limitation a merger, consolidation, statutory share exchange or reclassification
of the Common Shares (each of the foregoing being referred to herein as a
"Transaction"), in each case as a result of which Common Shares shall be
converted into the right to receive shares, securities or other property
(including cash or any combination thereof), each Series A Preferred Share which
is not converted into the right to receive shares, securities or other property
in connection with such Transaction shall thereupon be convertible into the kind
and amount of shares, securities and other property (including cash or any
combination thereof) receivable upon such consummation by a holder of that
number of Common Shares into which one Series A Preferred Share was convertible
immediately prior to such Transaction. The Trust shall not be a party to any
Transaction unless the terms of such Transaction are consistent with the
provisions of this paragraph (d), and it shall not consent or agree to the
occurrence of any Transaction until the Trust has entered into an agreement with
the successor or purchasing entity, as the case may be, for the benefit of the
holders of the Series A Preferred Shares that will contain provisions enabling
the holders of the Series A Preferred Shares that remain outstanding after such
Transaction to convert into the consideration received by holders of Common
Shares at the Conversion Rate. The provisions of this paragraph (d) shall
similarly apply to successive Transactions.




                                      6
<PAGE>


         (e) If there shall be any reclassification of the Common Shares or any
consolidation or merger to which the Trust is a party and for which approval of
any shareholders of the Trust is required, or a statutory share exchange, or the
voluntary or involuntary liquidation, dissolution and winding up of the Trust,
then the Trust shall cause to be mailed to each holder of Series A Preferred
Shares at such holder's address as shown on the records of the Trust, as
promptly as possible, but at least 15 days prior to the applicable date
hereinafter specified, a notice stating the date on which such reclassification,
consolidation, merger, statutory share exchange or liquidation, dissolution and
winding up is expected to become effective, and the date as of which it is
expected that holders of Common Shares of record shall be entitled to exchange
their Common Shares for securities or other property, if any, deliverable upon
such event. Failure to give or receive such notice or any defect therein shall
not affect the legality or validity of the proceedings described in this Section
6.

         (f) (i) In the event the Trust should at any time or from time to time
after the date of issuance of the Series A Preferred Shares fix a record date
for the effectuation of a split or subdivision of the outstanding Common Shares
or the determination of holders of Common Shares entitled to receive a dividend
or other distribution payable in additional Common Shares without payment of any
consideration by such holder for the additional Common Shares, then, as of such
record date (or the date of such dividend distribution, split or subdivision if
no record date is fixed), the Conversion Rate shall be appropriately increased
so that the number of Common Shares issuable on conversion of each Series A
Preferred Share shall be increased in proportion to such increase of outstanding
Common Shares and the Common Shares Dilution Price shall be correspondingly
decreased. If the number of Common Shares outstanding at any time after the date
of issuance of the Series A Preferred Shares is decreased by a combination of
the then outstanding Common Shares, then, following the record date of such
combination (or the date of such combination if no record date is fixed), the
Conversion Rate for the Series A Preferred Shares shall be appropriately
decreased so that the number of shares of Common Stock issuable on conversion of
each Series A Preferred Share shall be decreased in proportion to such decrease
in outstanding Common Shares and the Common Share Dilution Price shall be
correspondingly increased. Whenever the Conversion Rate and Common Share
Dilution Price are adjusted as herein provided, the Trust shall promptly file
with the Transfer Agent an officer's certificate setting forth the Conversion
Rate and Common Share Dilution Price after such adjustment and setting forth a
brief statement of the facts requiring such adjustment which certificate shall
be conclusive evidence of the correctness of such adjustment absent manifest
error. Promptly after delivery of such certificate, the Trust shall prepare a
notice of such adjustment setting forth the adjusted Conversion Rate and Common
Share Dilution Price and the effective date such adjustment becomes effective
and shall mail such notice of such adjustment to each holder of Series A
Preferred Shares at such holder's last address as shown on the share records of
the Trust.



<PAGE>


                  (ii) In the event the Trust at any time, or from time to time,
shall make or issue, or fix a record date for the determination of holders of
Common Shares entitled to receive, a dividend or other distribution payable in
securities of the Trust other than Common Shares, then




                                       7
<PAGE>



and in each such event,
provision shall be made so that the holders of Series A Preferred Shares shall
receive upon conversion thereof, in addition to the number of Common Shares
receivable thereupon, the amount of securities of the Trust which they would
have received had their Series A Preferred Shares been converted into Common
Share on the date of such event and had thereafter, during the period from the
date of such event to and including the date of conversion, retained such
securities receivable by them as aforesaid during such period, giving
application to all adjustments called for during such period under this Section
6(f) with respect to the rights of the holders of Series A Preferred Shares.

         (g) In any case in which paragraph (f) of this Section 6 provides that
an adjustment shall become effective on the day next following the record date
for an event, the Trust may defer until the occurrence of such event (A) issuing
to the holder of any Series A Preferred Share converted after such record date
and before the occurrence of such event the additional Common Shares issuable
upon such conversion by reason of the adjustment required by such event over and
above the Common Shares issuable upon such conversion before giving effect to
such adjustment and (B) paying to such holder any amount of cash in lieu of any
fraction pursuant to paragraph (c) of this Section 6; provided, however, that
the holder of such Series A Preferred Shares shall be entitled to such
additional Common Shares and cash, as applicable, upon such event.

         (h) There shall be no adjustment of the Conversion Rate in case of the
issuance of any capital shares of the Trust, including issuance in connection
with a reorganization, acquisition or other similar transaction except as
specifically set forth in this Section 6. If any action or transaction would
require adjustment of the Conversion Rate pursuant to more than one paragraph of
this Section 6, only one adjustment shall be made and such adjustment shall be
the amount of adjustment that has the highest absolute value to the holder of
Series A Preferred Shares.

         (i) The Trust shall at all times reserve and keep available, free from
preemptive rights, out of the aggregate of its authorized but unissued Common
Shares solely for the purpose of effecting conversion of the Series A Preferred
Shares, the full number of Common Shares deliverable upon the conversion of all
outstanding Series A Preferred Shares not theretofore converted into Common
Shares. For purposes of this paragraph (i), the number of Common Shares that
shall be deliverable upon the conversion of all outstanding Series A Preferred
Shares shall be computed as if at the time of computation all such outstanding
shares were held by a single holder. The Trust covenants that any Common Shares
issued upon conversion of the Series A Preferred Shares shall be validly issued,
fully paid and non-assessable. The Trust shall list the Common Shares required
to be delivered upon conversion of the Series A Preferred Shares, prior to such
delivery, upon each national securities exchange, if any, upon which the
outstanding Common Shares are listed at the time of such delivery.

         (j) The Trust will pay any and all documentary stamp or similar issue
or transfer taxes payable in respect of the issue or delivery of Common Shares
or other securities or property




                                      8
<PAGE>


on conversion of Series A Preferred Shares
pursuant hereto; provided, however, that the Trust shall not be required to pay
any tax that may be payable in respect of any transfer involved in the issue or
delivery of Common Shares or other securities or property in a name other than
that of the holder of the Series A Preferred Shares to be converted, and no such
issue or delivery shall be made unless and until the Person requesting such
issue or delivery has paid to the Trust the amount of any such tax or
established, to the reasonable satisfaction of the Trust, that such tax has been
paid.

         Section 7. Additional Parity and Junior Shares. Without vote or consent
of the holders of Series A Preferred Shares, the Trust may issue any class or
series of capital shares of the Trust with voting rights, if any, as determined
by the Trust which may rank:

         (a) on a parity with the Series A Preferred Shares, as to the payment
of dividends and as to distribution of assets upon liquidation, dissolution or
winding up, whether or not the dividend rates, dividend payment dates or
redemption or liquidation prices per share thereof be different from those of
the Series A Preferred Shares, if the holders of such class of Shares or series
and the Series A Preferred Shares shall be entitled to the receipt of dividends
and of amounts distributable upon liquidation, dissolution or winding up in
proportion to their respective amounts of accrued and unpaid dividends per share
or liquidation preferences, without preference or priority one over the other;

         (b) junior to the Series A Preferred Shares, as to the payment of
dividends or as to the distribution of assets upon liquidation, dissolution or
winding up, if such Shares or series shall be Common Shares or other Junior
Shares; and

         (c) prior or senior to the Series A Preferred Shares as to the payment
of dividends or distributions of assets upon liquidation, dissolution or winding
up; provided, however, that the vote of the holders of Series A Preferred Shares
required by paragraph (b) of Section 8 has been obtained, where applicable.

         Section 8.        Voting.

         (a) Except as otherwise provided in paragraphs (b) and (c) of this
Section 8, the holders of Series A Preferred Shares shall have no right to vote
on any matter to be voted on by the shareholders of the Trust (including,
without limitation, any election or removal of a Trustee), and the Series A
Preferred Shares shall not be included in the number of shares voting or
entitled to vote on such matters.

         (b) So long as any Series A Preferred Shares are outstanding, in
addition to any other vote or consent of shareholders required by law or by the
Declaration of Trust, the affirmative vote of at least 66 2/3% of the votes
entitled to be cast by the holders of the Series A Preferred Shares at the time
outstanding, acting as a single class, given in person or by proxy, either in
writing without a meeting or by vote at any meeting called for the purpose,
shall be necessary for



                                       9
<PAGE>


(i) an increase in the number of authorized shares of
Series A Preferred Shares, (ii) effecting or validating any amendment,
alteration or repeal of any of the provisions of these Articles, the Declaration
of Trust or the Bylaws of the Trust that adversely affects the voting powers,
rights or preferences of the holders of the Series A Preferred Shares or (iii)
consummating a Dilutive Transaction (as defined in paragraph (c) below) during
the Standstill Period. So long as not less than 100,000 Series A Preferred
Shares are outstanding excluding in such calculation the Tendered Non-Converted
Shares, the affirmative vote of at least 66_% of the votes entitled to be cast
by the holders of the Series A Preferred Shares at the time outstanding
(including the Tendered Non-Converted Shares), acting as a single class, given
in person or by proxy, either in writing or without a meeting or by vote at any
meeting called for the purpose, shall be necessary to create or authorize any
class or series of capital shares of the Trust ranking prior or senior to the
Series A Preferred Shares (or any class or series of partnership units of
Corporate Office Properties, L.P. of which the Trust is the general partner
ranking prior or senior to the Series A Preferred Units to be issued to the
Trust in connection with the issuance of the Series A Preferred Shares to
Constellation) as to the payment of dividends or as to distributions of assets
upon liquidation, dissolution or winding up. Notwithstanding the foregoing
provisions of this paragraph (b) of Section 8, any amendment of the provisions
of the Declaration of Trust (or the partnership agreement of Corporate Office
Properties, L.P.) so as to authorize or create, or to increase the authorized
amount of, any Junior Shares (or units of partnership interest with or without
voting rights junior as to the payment of dividends and as to asset
distributions to the Series A Units) or any shares of any class with or without
voting rights ranking on a parity with the Series A Preferred Shares (or Series
A Preferred Units) shall not be deemed to adversely affect the voting powers,
rights or preferences of the holders of Series A Preferred Shares (or Series A
Preferred Units). For the purpose of this paragraph, the holder of Series A
Preferred Shares shall have the right to one vote for each such Series A
Preferred Share.

         (c) For the purpose of paragraph (b) above, the term "Dilutive
Transaction" shall mean any transaction or series of related transactions during
the Standstill Period in which the Trust shall issue or sell Common Shares with
an aggregate then Current Market Price in excess of $50.0 million with a Common
Share price per share less than the Common Share Dilution Price. The term
"Common Share Dilution Price" shall mean $9.50 per share, subject to adjustment
as provided in paragraph (f) of Section 6. For the purpose of calculating the
aggregate Current Market Price of the Common Shares, securities convertible into
Common Shares or warrants, rights or options to purchase Common Shares at a
price less than the Common Share Dilution Price shall be deemed to have been
converted or exercised, as the case may be, into an additional number of Common
Shares at the time of the Dilutive Transaction, and the Trust shall be deemed to
have issued or sold such additional number of Common Shares at the time of, and
in connection with, the Dilutive Transaction.

         (d) So long as any Series A Preferred Shares are owned of record and
beneficially by Constellation and Constellation also owns of record and
beneficially at least 30% of the outstanding Common Shares, Constellation shall
be entitled to vote for and elect two members of the Board of Trustees. So long
as any Series A Preferred Shares are owned of record and




                                       10
<PAGE>


beneficially by
Constellation and Constellation also owns of record and beneficially less than
30% but more than 15% of the outstanding Common Shares, Constellation shall be
entitled to vote for and elect one member of the Board of Trustees. In
determining the percentage of the outstanding Common Shares for the purposes of
this paragraph, the Common Shares issuable upon conversion of any Series A
Preferred Shares owned by Constellation shall be deemed outstanding. If any
member of the Board of Trustees so elected by Constellation shall withdraw or be
removed from the Board for any reason, Constellation shall have the right to
elect the replacement for such member. Constellation shall have the right to
remove a Trustee elected by Constellation for any reason at any time. The term
of office of any Trustee elected by Constellation pursuant to this paragraph
shall expire on the date that Constellation no longer holds of record and
beneficially any Series A Preferred Shares and the percentage of Common Shares
required to elect that Trustee as provided in this paragraph. If two Trustees
have been elected by Constellation and the term of one Trustee expires by
operation of the preceding sentence, the Board of Trustees may determine which
Trustee shall have completed service on the Board absent a determination by
Constellation.

         (e) If the Trust shall fail at any time or from time to time to pay
when due two consecutive quarterly dividend payments on the Series A Preferred
Shares, then the holders of the Series A Preferred Shares shall be entitled to
elect two additional members to the Board of Trustees of the Trust to serve
until all accrued and unpaid dividends on the Preferred Shares have been paid in
full.

         Section 9. Record Holders. The Trust and the Transfer Agent may deem
and treat the record holder of any Series A Preferred Share as the true and
lawful owner thereof for all purposes, and neither the Trust nor the Transfer
Agent shall be affected by any notice to the contrary.

Ratification and Authorization

         RESOLVED, that any and all acts and deeds of any officer or Trustee
taken prior to the date hereof on behalf of the Trust with regard to the
foregoing resolutions are hereby approved, ratified and confirmed in all
respects as and for the acts and deeds of the Trust.

         FURTHER RESOLVED, that the officers of the Trust be, and each of them
hereby is, severally and without the necessity for joinder of any other Person,
authorized, empowered and directed to execute and deliver any and all such
further documents and instruments and to do and perform any and all such further
acts and deeds that may be necessary or advisable to effectuate and carry out
the purposes and intents of the foregoing resolutions, including, but not
limited to, the filing of Articles Supplementary pursuant to Maryland REIT Law
with the State Department of Assessments and Taxation of Maryland, setting forth
the designations, preferences, limitations and rights of Series A Preferred
Shares pursuant to Section 8-203(b) of the Maryland REIT Law, all such actions
to be performed in such manner, and all such documents and instruments to be
executed and delivered in such form, as the officer performing or executing the
same shall




                                       11
<PAGE>


approve, the performance or execution thereof by such officer to be
conclusive evidence of the approval thereof by such officer and by the Board of
Trustees.




                                       12




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