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Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
One Financial Center
Boston, Massachusetts 02111
617 542 6000
617 542 2241 FAX
January 2, 2001
ImmunoGen, Inc.
128 Sidney Street
Cambridge, Massachusetts 02139
Ladies and Gentlemen:
We have acted as counsel to ImmunoGen Inc., a Massachusetts
corporation (the "Company"), in connection with the preparation and filing with
the Securities and Exchange Commission of a Registration Statement on Form S-8
(the "Registration Statement"), pursuant to which the Company is registering the
issuance of a total of One Million Three Hundred Twenty-Five Thousand
(1,325,000) shares (the "Shares") of its common stock, $.01 par value per share,
(the "Common Stock") under the Securities Act of 1933, as amended. This opinion
is being rendered in connection with the filing of the Registration Statement.
All capitalized terms used herein and not otherwise defined shall have the
respective meanings given to them in the Registration Statement.
In connection with this opinion, we have examined the Company's
Restated Articles of Organization and By-Laws, both as currently in effect; such
other records of the corporate proceedings of the Company and certificates of
the Company's officers as we have deemed relevant; and the Registration
Statement and the exhibits thereto.
In our examination, we have assumed the genuineness of all
signatures, the legal capacity of natural persons, the authenticity of all
documents submitted to us as originals, the conformity to original documents of
all documents submitted to us as certified or photostatic copies and the
authenticity of the originals of such copies.
Based upon the foregoing, we are of the opinion that (i) the
Shares have been duly and validly authorized by the Company and (ii) the
Shares, when sold, will have been duly and validly issued, fully paid
and non-assessable shares of the Company.
Our opinion is limited to the Business Corporation Laws of the
Commonwealth of Massachusetts, and we express no opinion with respect to the
laws of any other jurisdiction. No opinion is expressed herein with respect to
the qualification of the Shares under the securities or blue sky laws of any
state or any foreign jurisdiction.
BOSTON NEW YORK RESTON WASHINGTON NEW HAVEN
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We understand that you wish to file this opinion as an exhibit to the
Registration Statement, and we hereby consent thereto.
Very truly yours,
/s/ Mintz, Levin, Cohn, Ferris,
Glovsky and Popeo, P.C.
MINTZ, LEVIN, COHN, FERRIS,
GLOVSKY AND POPEO, P.C.
