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                                                                     EXHIBIT 8.1

 
           [LETTERHEAD OF GOODWIN, PROCTER & HOAR LLP APPEARS HERE]

                                 June 12, 1997



Boston Properties, Inc.
8 Arlington Street
Boston, MA 02116


Ladies and Gentlemen:

     We have acted as counsel to Boston Properties, Inc., a Delaware corporation
(the "Company"), in connection with the preparation of a registration statement
(the "Registration Statement") filed with the Securities and Exchange Commission
on April 16, 1997 on Form S-11 (No. 333-25279), as amended through the date
hereof, with respect to the offering and sale (the "Offering") of up to
31,400,000 shares of common stock, par value $.01 per share ("Common Stock") of
the Company, and the Company's contribution of substantially all of the net
proceeds of the Offering to Boston Properties, Limited Partnership, a Delaware
limited partnership organized on April 8, 1997 (the "Operating Partnership"), in
exchange for a general partnership interest and a limited partnership interest
therein. You have requested our opinion on certain federal income tax matters in
connection with the Offering.

     In connection with the completion of the Offering, (i) pursuant to one or
more options, contribution or merger agreements, certain partnerships (each a
"Property Partnership") that currently own properties that will be owned,
directly or indirectly, by the Company (each a "Property" and collectively the
"Properties") will contribute their Properties to the Operating Partnership, or
will merge with and into the Operating Partnership, in exchange for OP Units and
the assumption of debt, and the partners of each such Property Partnership will
receive OP Units either directly as merger consideration or as a distribution
from one or more of the Property Partnerships; (ii) direct and indirect interest
in other Property Partnerships will be contributed to the Operating Partnership
in exchange for OP Units; (iii) the Company through the Operating Partnership
will contribute substantially all of its greater Washington, D.C. property
management business to Boston Properties Management, Inc. (the "Management
Company"), a Delaware corporation organized on June 10, 1997.  The Operating
Partnership owns a 1% voting interest representing a 95% economic interest in
the Management Company.  The remaining voting and economic interest are held by
Mortimer B. Zuckerman and Edward H. Linde, officers and directors of the
Management Company; (iv) the other management and development operations 
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Boston Properties, Inc.
June 12, 1997
Page 2


 
of the Company will be contributed directly to the Operating Partnership; and
(v) the Operating Partnership will enter into a participating lease with ZL
Hotel LLC, a Delaware limited liability company organized on June 10, 1997
formed to be the lessee of the Company's hotel Properties. Mortimer B. Zuckerman
and Edward H. Linde, shareholders of the Company will be the sole member
managers of the ZL Hotel LLC and own a 9.8% economic interest in ZL Hotel LLC.
ZL Hotel Corp., a pre-existing Delaware corporation will own the remaining
economic interest in ZL Hotel LLC and one or more public charities will own all
of the capital stock of ZL Hotel Corp.

     References herein to the Subsidiaries includes (i) the Operating
Partnership; (ii) the Management Company; (iii) Boston Properties LLC, a
Delaware limited liability company formed on June 10, 1997, of which the Company
is a 1% member and the Operating Partnership is a 99% member manager,
established to own general partnership interests in various New York, D.C. and
Maryland Property Partnerships the limited partner interest in which will be
held by the Operating Partnership; (iv) BP Lex LLC, a Delaware limited liability
company formed on June 10, 1997, to manage one of the New York Properties and in
which a 99.9% membership interest will be held by the Operating Partnership and
a .1% member-manager interest will be held, in the aggregate, by Mortimer B.
Zuckerman and Edward H. Linde; and (v) the Property Partnerships in which
interests will be contributed to the Operating Partnership in exchange for OP
Units in connection with the Offering.

     Capitalized terms not defined herein shall have the same meaning as in the
Registration Statement.

     In rendering the following opinions, we have examined the Amended and
Restated Certificate of Incorporation (the "Articles") and Bylaws of the
Company, and such other records, certificates and documents as we have deemed
necessary or appropriate for purposes of rendering the opinion set forth herein
(collectively, the "Documents").  We have reviewed the proposed investment
activities, operations and governance of the Company and its Subsidiaries.  We
have relied upon representations of duly appointed officers of the Company and
the Operating Partnership (including without limitation, representations
contained in a letter dated as of this date (the "Officer's Certificate")),
principally relating to the Company's organization and operations.  We assume
that each such representation is and will be true, correct and complete and that
all representations that speak in the future, or to the intention, or to the
best of the belief and knowledge of any person(s) or party(ies) are and will be
true, correct and complete as if made without such qualification.  Nothing has
come to our attention which would cause us to believe that any of such
representations are untrue, incorrect or incomplete.  We assume that the Company
will be operated in accordance with the applicable laws and the terms and
conditions 

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Boston Properties, Inc.
June 12, 1997
Page 3


of applicable documents. We have also reviewed the Registration Statement,
including the prospectus (the "Prospectus") contained as part of the
Registration Statement, the form of Amended and Restated Agreement of Limited
Partnership of the Operating Partnership to be executed as of the date of the
closing of the Offering, among the Company as the general partner and several
limited partners; the participating leases with respect to the hotel properties
entered into between the Operating Partnership as lessor and ZL Hotel LC as
lessee, and certain other leases as we have deemed appropriate. In addition, we
have relied upon certain additional facts and assumptions described below.

     In rendering the opinion set forth herein, we have assumed (i) the
genuineness of all signatures on documents we have examined, (ii) the
authenticity of all documents submitted to us as originals, (iii) the conformity
to the original documents of all documents submitted to us as copies, (iv) the
conformity of final documents to all documents submitted to us as drafts, (v)
the authority and capacity of the individual or individuals who executed any
such documents on behalf of any person, (vi) the accuracy and completeness of
all records made available to us, and (vii) the factual accuracy of all
representations, warranties and other statements made by all parties.  In
addition, we assume that all interests in the Operating Partnership will be
issued in a transaction (or transactions) that are not required to be registered
under the Securities Act of 1933 and that no interest in the Operating
Partnership offered for sale outside the United States would have been required
to be registered under the Securities Act of 1933 if such interest had been
offered for sale within the United States.  We have further assumed that during
its short 1997 taxable year ending December 31, 1997 and subsequent taxable
years, the Company will operate in such a manner that will make the
representations contained in the Officer's Certificate true for all such years,
and that the Company and its Subsidiaries will not make any amendments to its
organizational documents after the date of this opinion that would affect the
Company's qualification as a real estate investment trust for any taxable year.
In addition, we have assumed that the Company will make an election to be
taxable as a real estate investment trust pursuant to the Internal Revenue Code
of 1986, as amended (the "Code") with its properly and timely filed federal
income tax return for its taxable year ending December 1997.  For purposes of
our opinion, we have made no independent investigation of the facts contained in
the documents and assumptions set forth above, the representations set forth in
the Officer's Certificate, or the Registration Statement.  No facts have come to
our attention, however, that would cause us to question the accuracy and
completeness of such facts or documents in a material way.

     The discussion and conclusion set forth below are based upon the Code, the
Income Tax Regulations and Procedure and Administration Regulations promulgated
thereunder and existing administrative and judicial interpretation thereof, all
of which are subject to change.  No assurance can therefore be given that the
federal income tax consequences described below will 


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Boston Properties, Inc.
June 12, 1997
Page 4

 
not be altered in the future. Based on the documents and assumptions set forth
above, the representations set forth in the Officer's Certificate and the
discussion in the Prospectus under the caption "Federal Income Tax
Considerations" (which is incorporated herein by reference), we are of the
opinion that

     (1) Commencing with the Company's initial taxable year ending December 31,
1997, the Company has been organized in conformity with the requirements for
qualification as a real estate investment trust under the Code, and its proposed
method of operation, including the lease of the Hotel Properties and the Garage
Properties, will enable it to meet the requirements for qualification as a "real
estate investment trust" under the Code provided that the Company files a proper
election to be taxed as a real estate investment trust with its timely filed
federal income tax return for the taxable year ending December 31, 1997 and
continues to meet the applicable asset composition, source of income,
shareholder diversification, distribution, record keeping and other requirements
of the Code necessary for a corporation to qualify as a real estate investment
trust, and

     (2) The information in the Registration Statement under the caption
"Federal Income Tax Considerations" to the extent that it constitutes matters of
law or legal conclusions, have been reviewed by us and is correct in all
material respects, and our opinion set forth in such discussion is confirmed.

     We will not review on a continuing basis the Company's compliance with the
documents or assumptions set forth above, or the representations set forth in
the Officer's Certificate. Accordingly, no assurance can be given that the
actual results of the Company's operations for any given taxable year will
satisfy the requirements for qualification and taxation as a real estate
investment trust under the Code.  The ability of the Company to continue to meet
the requirements for qualification and taxation as a real estate investment
trust will be dependent upon the Company's ability to continue to meet in each
year the applicable asset composition, source of income, shareholder
diversification, distribution, record keeping and other requirements of the Code
necessary for a corporation to qualify as a real estate investment trust. The
foregoing opinions are limited to the federal income tax matters addressed
herein, and no other opinions are rendered with respect to other federal tax
matters or to any issues arising out of the tax laws of any state or locality.
We express no opinion with respect to the transactions described herein other
than those expressly set forth herein.  You should recognize that our opinion is
not binding on the IRS and that the IRS may disagree with the opinions contained
herein.  Although we believe that our opinion will be sustained if challenged,
there is no guarantee that this will be the case.  Except as specifically
discussed above, the opinion expressed herein is based upon the laws that
currently exist.  Consequently, future changes in the 

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Boston Properties, Inc.
June 12, 1997
Page 5

 
law may cause the federal income tax treatment of the transactions herein to be
materially and adversely different from that described above.

     We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement.  We also consent to the references to Goodwin, Procter &
Hoar LLP under the caption "Federal Income Tax Considerations" in the
Registration Statement.  In giving this consent, we do not admit that we are in
the category of persons whose consent is required by Section 7 of the Securities
Act of 1933, as amended, or the rules and regulations promulgated thereunder by
the Securities and Exchange Commission.

                              Very truly yours,

                              /s/ Goodwin, Procter & Hoar  LLP

                              Goodwin, Procter & Hoar  LLP

