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                                                                     Exhibit 4.6

                      BOSTON PROPERTIES LIMITED PARTNERSHIP

                                     ISSUER

                                       to

                              THE BANK OF NEW YORK

                                     TRUSTEE

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


                          Supplemental Indenture No. 3

                           Dated as of March 18, 2003

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


                                  $300,000,000

                                       of

                          5.625% Senior Notes due 2015

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                                TABLE OF CONTENTS

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<Caption>
                                                                                                      PAGE
   <S>              <C>                                                                                 <C>
                                   ARTICLE ONE
                    RELATION TO SENIOR INDENTURE; DEFINITIONS

   SECTION 1.1.         Relation to Senior Indenture.....................................................1
   SECTION 1.2.         Definitions......................................................................2

                                   ARTICLE TWO
                                    THE NOTES

   SECTION 2.1.         Title of the Securities.........................................................12
   SECTION 2.2.         Limitation on Aggregate Principal Amount........................................12
   SECTION 2.3.         Interest and Interest Rates; Maturity Date of Notes.............................13
   SECTION 2.4.         Limitations on Incurrence of Debt...............................................14
   SECTION 2.5.         Optional Redemption.............................................................15
   SECTION 2.6.         Places of Payment...............................................................16
   SECTION 2.7.         Method of Payment...............................................................16
   SECTION 2.8.         Currency........................................................................16
   SECTION 2.9.         Registered Securities; Global Form..............................................16
   SECTION 2.10.         Form of Notes..................................................................17
   SECTION 2.11.         Transfer and Exchange..........................................................17
   SECTION 2.12.         General Provisions Relating to Transfers and Exchanges.........................25
   SECTION 2.13.         Registrar and Paying Agent.....................................................26
   SECTION 2.14.         Defeasance.....................................................................26
   SECTION 2.15.         Provision of Financial Information.............................................26
   SECTION 2.16.         Waiver of Certain Covenants....................................................27
   SECTION 2.17.         No Sinking Fund................................................................27
   SECTION 2.18.         No Repayment at Option of Holders..............................................27
   SECTION 2.19.         Designation of CBD Properties..................................................27

                                  ARTICLE THREE
                            MISCELLANEOUS PROVISIONS

   SECTION 3.1.         Ratification of Senior Indenture................................................28
   SECTION 3.2.         Governing Law...................................................................28
   SECTION 3.3.         Counterparts....................................................................28
   SECTION 3.4.         Trustee.........................................................................28

   SCHEDULE A           -   SC-A-1
   SCHEDULE B           -   SC-B-1
   EXHIBIT A            -   A-1
   EXHIBIT B            -   B-1
   EXHIBIT C            -   C-1
</Table>

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     THIS SUPPLEMENTAL INDENTURE NO. 3, dated as of March 18, 2003 (the "Third
Supplemental Indenture"), between BOSTON PROPERTIES LIMITED PARTNERSHIP, a
limited partnership organized under the laws of the State of Delaware (herein
called the "Company"), and THE BANK OF NEW YORK, a New York banking corporation,
as trustee (herein called the "Trustee").

                             RECITALS OF THE COMPANY

     The Company has heretofore delivered to the Trustee an Indenture dated as
of December 13, 2002 (the "Senior Indenture"), providing for the issuance by the
Company from time to time of its senior debt securities evidencing its unsecured
and unsubordinated indebtedness (the "Securities").

     Section 3.01 of the Senior Indenture provides for various matters with
respect to any series of Securities issued under the Senior Indenture to be
established in an indenture supplemental to the Senior Indenture.

     Section 9.01(7) of the Senior Indenture provides for the Company and the
Trustee to enter into an indenture supplemental to the Senior Indenture to
establish the form or terms of Securities of any series as provided by Sections
2.01 and 3.01 of the Senior Indenture.

     The Board of Directors of Boston Properties, Inc., the general partner of
the Company, has duly adopted resolutions authorizing the Company to execute and
deliver this Third Supplemental Indenture.

     All of the conditions and requirements necessary to make this Third
Supplemental Indenture, when duly executed and delivered, a valid and binding
agreement in accordance with its terms and for the purposes herein expressed,
have been performed and fulfilled.

NOW, THEREFORE, THIS THIRD SUPPLEMENTAL INDENTURE WITNESSETH:

     For and in consideration of the premises and the purchase of the series of
Securities provided for herein by the Holders thereof, it is mutually covenanted
and agreed, for the equal and proportionate benefit of all Holders of Securities
of such series, as follows:

                                   ARTICLE ONE

                    RELATION TO SENIOR INDENTURE; DEFINITIONS

     SECTION 1.1.   RELATION TO SENIOR INDENTURE.

     This Third Supplemental Indenture constitutes an integral part of the
Senior Indenture.

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     SECTION 1.2.   DEFINITIONS.

     For all purposes of this Third Supplemental Indenture, except as otherwise
expressly provided for or unless the context otherwise requires:

          (1) Capitalized terms used but not defined herein shall have the
     respective meanings assigned to them in the Senior Indenture; and

          (2) All references herein to Articles and Sections, unless otherwise
     specified, refer to the corresponding Articles and Sections of this Third
     Supplemental Indenture.

     "ADDITIONAL INTEREST" has the meaning specified in Section 2.3(d) hereof.

     "ANNUALIZED CONSOLIDATED EBITDA" means, for any quarter, the product of
Consolidated EBITDA for such period of time multiplied by four (4), PROVIDED
that any non-recurring item that is an expense shall be added back to net income
in determining such Consolidated EBITDA before such multiplication and deducted
once from such product, and FURTHER PROVIDED that any non-recurring item that is
income shall be added to such product once and shall not be multiplied by four.

     "ANNUALIZED INTEREST EXPENSE" means, for any quarter, the Interest Expense
for that quarter multiplied by four (4).

     "ANOTHER PERSON'S SHARE" means, in connection with the defined term
"Contingent Liabilities of Boston Properties Limited Partnership and
Subsidiaries", (1) the aggregate direct and indirect interests of each Person
other than the Company or any of its Subsidiaries in the equity capital of the
applicable Partially-Owned Entity, calculated by subtracting from 100% the
Percentage Interest with respect to such Partially-Owned Entity, or (2) in the
case of reimbursement owed to the Company or any of its Subsidiaries by a third
party in respect of payment made under a guaranty, the amount to be reimbursed
to the Company or any of its Subsidiaries by such third party.

     "APPLICABLE PROCEDURES" means, with respect to any transfer or exchange of
or for beneficial interests in any Global Note, the rules and procedures of the
Depositary, Euroclear or Clearstream, as the case may be, that apply to such
transfer or exchange.

     "CAPITALIZATION RATE" means: (i) 9.0% for properties other than the CBD
Properties, and (ii) 8.5% for properties which are CBD Properties.

     "CAPITALIZED PROPERTY VALUE" means, as of any date, the sum of (1) with
respect to CBD Properties and non-CBD Properties, in each case that are not
hotel properties, the aggregate sum of all Property EBITDA for each such CBD
Property and non-CBD Property for the Latest Completed Quarter prior to such
date, annualized (i.e., multiplied by four (4)), and capitalized at the
applicable Capitalization Rate PLUS (2) with respect to CBD Properties and
non-CBD Properties, in each case that are hotel properties, the aggregate sum of
all Property EBITDA for each such CBD Property and non-CBD Property for the most
recent four (4) consecutive completed fiscal quarters, capitalized at

                                        2
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the applicable Capitalization Rate; PROVIDED, HOWEVER, that if the value of a
particular property calculated pursuant to clause (1) or (2) above, as
applicable, is less than the undepreciated book value of such property, as
determined in accordance with GAAP, such undepreciated book value shall be used
in lieu thereof with respect to such property.

     "CBD PROPERTIES" means each of the properties set forth on SCHEDULE A
attached hereto, together with each additional property which is, from time to
time, designated by the Company as a CBD Property in accordance with Section
2.19 hereof.

     "CBD MARKETS" means each of the markets set forth on SCHEDULE B attached
hereto.

     "CLOSING DATE" has the meaning assigned to such term in the Registration
Rights Agreement.

     "COMPARABLE TREASURY ISSUE" means the United States Treasury security
selected by an Independent Investment Banker as having a maturity comparable to
the remaining term of the Notes that would be utilized, at the time of selection
and in accordance with customary financial practice, in pricing new issues of
corporate debt securities of comparable maturity to the remaining term of such
Notes.

     "COMPARABLE TREASURY PRICE" means, with respect to any Redemption Date, (a)
the bid price for the Comparable Treasury Issue (expressed as a percentage of
its principal amount) at 4:00 P.M. on the third business day preceding such
Redemption Date, as set forth on "Telerate Page 500" (or such other page as may
replace Telerate Page 500), or (b) if such page (or any successor page) is not
displayed or does not contain such bid prices at such time (i) the average of
the Reference Treasury Dealer Quotations obtained by the Trustee for such
Redemption Date, after excluding the highest and lowest of four such Reference
Treasury Dealer Quotations, or (ii) if the Trustee is unable to obtain at least
four such Reference Treasury Dealers Quotations, the average of all Reference
Treasury Dealer Quotations obtained by the Trustee.

     "CONSOLIDATED EBITDA" means, for any period of time, without duplication
(1) net income (loss), excluding net derivative gains and gains (losses) on
dispositions of real estate, before deductions for (i) Interest Expense, (ii)
taxes, (iii) depreciation, amortization, net derivative losses and all other
non-cash items, as determined in good faith by the Company, deducted in arriving
at net income (loss), (iv) extraordinary items, (v) non-recurring items, as
determined in good faith by the Company (including prepayment penalties), and
(vi) minority interest, of the Company and its Subsidiaries; PLUS (2) the
product of (A) net income (loss), excluding net derivative gains and gains
(losses) on dispositions of real estate, before deductions for (i) interest
expense, (ii) taxes, (iii) depreciation, amortization, net derivative losses and
all other non-cash items, as determined in good faith by the Company, deducted
in arriving at net income (loss), (iv) extraordinary items, and (v)
non-recurring items, as determined in good faith by the Company (including
prepayment penalties), of Partially-Owned Entities, multiplied by (B) the
Company's and its Subsidiaries' percentage share of such Partially-Owned
Entities; MINUS (3) the Company's income (loss) from Partially-Owned Entities.
In each

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of cases (1), (2) and (3) for such period, amounts shall be as reasonably
determined by the Company in accordance with GAAP, except to the extent GAAP is
not applicable with respect to the determination of all non-cash and
non-recurring items. Consolidated EBITDA shall be adjusted, without duplication,
to give pro forma effect: (x) in the case of any assets having been
placed-in-service or removed from service since the beginning of the period and
on or prior to the date of determination, to include or exclude, as the case may
be, any Consolidated EBITDA earned or eliminated as a result of the placement of
such assets in service or removal of such assets from service as if the
placement of such assets in service or removal of such assets from service
occurred at the beginning of the period; and (y) in the case of any acquisition
or disposition of any asset or group of assets since the beginning of the period
and on or prior to the date of determination, including, without limitation, by
merger, or stock or asset purchase or sale, to include or exclude, as the case
may be, any Consolidated EBITDA earned or eliminated as a result of the
acquisition or disposition of those assets as if the acquisition or disposition
occurred at the beginning of the period.

     "CONSOLIDATED FINANCIAL STATEMENTS" means, with respect to any Person,
collectively, the consolidated financial statements and notes to those financial
statements, of that Person and its subsidiaries prepared in accordance with
GAAP. For purposes of this definition, if as of any date or for any period
actual consolidated financial statements of any Person have not been prepared,
then this term shall include the books and records of that Person ordinarily
used in the preparation of such financial statements.

     "CONTINGENT LIABILITIES OF BOSTON PROPERTIES LIMITED PARTNERSHIP AND
SUBSIDIARIES" means, as of any date, without duplication, those liabilities of
the Company or any of its Subsidiaries consisting of indebtedness for borrowed
money, as determined in accordance with GAAP, that are or would be stated and
quantified as contingent liabilities in the notes to the Consolidated Financial
Statements of the Company as of that date; PROVIDED, HOWEVER, that Contingent
Liabilities of Boston Properties Limited Partnership and Subsidiaries shall
exclude Another Person's Share of Duplicated Obligations.

     "DEBT" means, as of any date, without duplication, (1) in the case of the
Company, all indebtedness and liabilities for borrowed money, secured or
unsecured, of the Company, including the Notes to the extent outstanding from
time to time; (2) in the case of the Company's Subsidiaries, all indebtedness
and liabilities for borrowed money, secured or unsecured, of the Subsidiaries,
including in each of cases (1) and (2) mortgage and other notes payable, but
excluding in each of cases (1) and (2) any indebtedness, including mortgages and
other notes payable, which is secured by cash, cash equivalents or marketable
securities or defeased (it being understood that cash collateral shall be deemed
to include cash deposited with a trustee with respect to third party
indebtedness; PROVIDED that such trustee holds such cash for not more than 60
days from the date of deposit); and (3) all Contingent Liabilities of Boston
Properties Limited Partnership and Subsidiaries. It is understood that Debt
shall not include any redeemable equity interest in the Company.

     "DEFAULTED INTEREST" has the meaning specified in Section 2.3 hereof.

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     "DEFINITIVE NOTE" means a certificated Note in the form of EXHIBIT A
hereto, registered in the name of the Holder thereof and issued in accordance
with Section 2.11 hereof, except that such Note shall not bear the Global Note
Legend.

     "DEPOSITARY" has the meaning assigned to it in Section 2.9(a) hereof.

     "DUPLICATED OBLIGATIONS" means, as of any date, collectively, all those
payment guaranties in respect of indebtedness and other liabilities, secured or
unsecured, of Partially-Owned Entities, including mortgage and other notes
payable, for which (1) the Company or any of its Subsidiaries, on the one hand,
and another Person or Persons, on the other hand, are jointly and severally
liable or (2) the Company or any of its Subsidiaries are entitled to
reimbursement in respect of payment under such guaranties from another Person or
Persons.

     "EXCHANGE NOTES" means the debt securities of the Company to be offered to
Holders in exchange for Initial Notes pursuant to the Exchange Offer or
otherwise pursuant to a registration of debt securities containing terms
identical in all material respects to the Notes for which they are exchanged.

     "EXCHANGE OFFER" means the exchange offer by the Company of Exchange Notes
for Initial Notes pursuant to the Registration Rights Agreement.

     "EXCHANGE OFFER REGISTRATION STATEMENT" has the meaning assigned to such
term in the Registration Rights Agreement.

     "GAAP" means generally accepted accounting principles in the United States,
consistently applied, as in effect from time to time.

     "GLOBAL NOTES" means, individually or collectively, any of the Notes issued
as Global Securities under the Senior Indenture.

     "GLOBAL NOTE LEGEND" means the legend set forth in Section 2.03 of the
Senior Indenture, which is required to be placed on all Global Notes issued
under the Senior Indenture.

     "HOLDERS" has the meaning specified in Section 2.3 hereof.

     "INCUR" means, with respect to any Debt or other obligation of any Person,
to create, assume, guarantee or otherwise become liable in respect of the Debt
or other obligation, and "Incurrence" and "Incurred" have the meanings
correlative to the foregoing.

     "INDEPENDENT INVESTMENT BANKER" means Salomon Smith Barney Inc., Banc of
America Securities LLC, J.P. Morgan Securities Inc. or such other independent
investment banking institution of national standing appointed by the Company.

     "INDIRECT PARTICIPANT" means a Person who holds a beneficial interest in a
Global Note through a Participant.

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     "INITIAL NOTES" means the Notes issued under this Third Supplemental
Indenture which are not Exchange Notes.

     "INITIAL PURCHASERS" has the meaning assigned to such term in the
Registration Rights Agreement.

     "INTERCOMPANY DEBT" means, as of any date, Debt to which the only parties
are Boston Properties, the Company, any Subsidiary of either of them as of that
date or any Partially-Owned Entity.

     "INTEREST EXPENSE" means, for any period of time, the aggregate amount of
interest recorded in accordance with GAAP for such period of time by the Company
and its Subsidiaries, but EXCLUDING: (i) interest reserves funded from the
proceeds of any loan and (ii) amortization of deferred financing costs; and
INCLUDING, without duplication: (A) effective interest in respect of original
issue discount as determined in accordance with GAAP; and (B) without limitation
or duplication, the interest expense (determined as provided above) of
Partially-Owned Entities, multiplied by the Company's Percentage Interest of the
Partially-Owned Entity Outstanding Debt in such Partially-Owned Entities, in all
cases as reflected in the applicable Consolidated Financial Statements.

         "INTEREST PAYMENT DATE" has the meaning specified in Section 2.3
hereof.

     "LATEST COMPLETED QUARTER" means the most recently ended fiscal quarter of
the Company for which Consolidated Financial Statements of the Company have been
completed, it being understood that at any time when the Company is subject to
the informational requirements of the Exchange Act, and in accordance therewith
files annual and quarterly reports with the Commission, the term "Latest
Completed Quarter" shall be deemed to refer to the fiscal quarter covered by the
Company's most recently filed Quarterly Report on Form 10-Q, or, in the case of
the last fiscal quarter of the year, the Company's Annual Report on Form 10-K.

     "LETTER OF TRANSMITTAL" means the letter of transmittal to be prepared by
the Company and sent to all Holders of the Notes for use by such Holders in
connection with the Exchange Offer.

     "LIEN" means, without duplication, any lien, mortgage, trust deed, deed of
trust, deed to secure debt, pledge, security interest, assignment for collateral
purposes, deposit arrangement, or other security agreement, excluding any right
of setoff but including, without limitation, any conditional sale or other title
retention agreement, any financing lease having substantially the same economic
effect as any of the foregoing, and any other like agreement granting or
conveying a security interest; PROVIDED, that for purposes hereof, "Lien" shall
not include any mortgage that has been defeased by the Company, any of its
Subsidiaries or any of the Partially-Owned Entities in accordance with the
provisions thereof through the deposit of cash, cash equivalents or marketable
securities (it being understood that cash collateral shall be deemed to include
cash deposited with a trustee with respect to third party indebtedness).

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     "NON-U.S. PERSON" means a Person who is not a U.S. Person.

     "NOTES" has the meaning specified in Section 2.1 hereof. For all purposes
of this Third Supplemental Indenture, the term "Notes" shall include the Initial
Notes and any Exchange Notes to be issued and exchanged for any Initial Notes
pursuant to the Registration Rights Agreement and this Third Supplemental
Indenture and, for purposes of this Third Supplemental Indenture, all Initial
Notes and Exchange Notes shall vote together as one series of Notes under the
Senior Indenture.

     "PARTIALLY-OWNED ENTITY" means, at any time, any of the partnerships,
associations, corporations, limited liability companies, trusts, joint ventures
or other business entities in which the Company, directly, or indirectly through
full or partial ownership of another entity, owns an equity interest, but which
is not required in accordance with GAAP to be consolidated with the Company for
financial reporting purposes.

     "PARTIALLY-OWNED ENTITY OUTSTANDING DEBT" means, as of any date, the
aggregate principal amount of all outstanding indebtedness and liabilities for
borrowed money, secured or unsecured, of the applicable Partially-Owned Entity,
including mortgage and other notes payable but excluding any indebtedness which
is secured by cash, cash equivalents or marketable securities or defeased (it
being understood that cash collateral shall be deemed to include cash deposited
with a trustee with respect to third party indebtedness), all as reflected in
the Consolidated Financial Statements of such Partially-Owned Entity as of such
date.

     "PARTICIPANT" means, with respect to Euroclear, Clearstream or the
Depositary, a Person who has an account with Euroclear, Clearstream or the
Depositary, as the case may be (and, with respect to The Depository Trust
Company, shall include Euroclear and Clearstream).

     "PARTICIPATING BROKER-DEALER" has the meaning assigned to such term in the
Registration Rights Agreement.

     "PERCENTAGE INTEREST" means, with respect to a Partially-Owned Entity, the
Company's direct or indirect interest in the equity capital of such entity
without giving effect to any incentive or performance-based sharing in the
entity's cash flow from operations or proceeds from capital transactions in
excess of such equity interest.

     "PROPERTY EBITDA" means for any property, CBD Property or non-CBD Property,
for any period of time, without duplication, (1) if the property is owned by the
Company or any of its Subsidiaries, the net income (loss) derived from such
property, excluding net derivative gains and gains (losses) on dispositions of
real estate, before deductions for (i) Interest Expense, (ii) taxes, (iii)
depreciation, amortization, net derivative losses and all other non-cash items,
as determined in good faith by the Company, deducted in arriving at net income
(loss), (iv) extraordinary items, (v) non-recurring items, as determined in good
faith by the Company (including prepayment penalties), and (vi) minority
interest, and (2) if the property is owned by a Partially-Owned

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Entity, the product of (A) net income (loss) derived from such property,
excluding net derivative gains and gains (losses) on dispositions of real
estate, before deductions for (i) interest expense, (ii) taxes, (iii)
depreciation, amortization, net derivative losses and all other non-cash items,
as determined in good faith by the Company, deducted in arriving at net income
(loss), (iv) extraordinary items, and (v) non-recurring items, as determined in
good faith by the Company (including prepayment penalties), multiplied by (B)
the Company's and its Subsidiaries' percentage share of such Partially-Owned
Entity. In each of cases (1) and (2) for such period, amounts shall be as
reasonably determined by the Company in accordance with GAAP, except to the
extent GAAP is not applicable with respect to the determination of all non-cash
and non-recurring items. Property EBITDA shall be adjusted, without duplication,
to give pro forma effect: (x) in the case of any assets having been
placed-in-service or removed from service since the beginning of the period and
on or prior to the date of determination, to include or exclude, as the case may
be, any Property EBITDA earned or eliminated as a result of the placement of
such assets in service or removal of such assets from service as if the
placement of such assets in service or removal of such assets from service
occurred at the beginning of the period; and (y) in the case of any acquisition
or disposition of any asset or group of assets since the beginning of the period
and on or prior to the date of determination, including, without limitation, by
merger, or stock or asset purchase or sale, to include or exclude, as the case
may be, any Property EBITDA earned or eliminated as a result of the acquisition
or disposition of those assets as if the acquisition or disposition occurred at
the beginning of the period. For purposes of this definition, in the case of (1)
and (2) above, Property EBITDA shall exclude general and administrative expenses
as reflected in the Company's audited year-end Consolidated Financial Statements
or reviewed interim Consolidated Financial Statements available for the Latest
Completed Quarter or the most recent four (4) consecutive completed fiscal
quarters, as applicable.

     "QIB" means a "qualified institutional buyer" as defined in Rule 144A.

     "QUALIFIED PERSON" means a "qualified person" within the meaning of Code
Section 49(a)(1)(D)(iv).

     "REFERENCE TREASURY DEALER" means, Salomon Smith Barney Inc., Banc of
America Securities LLC and J.P. Morgan Securities Inc. (and their respective
successors) or such other primary U.S. Government securities dealer appointed by
the Company and three other primary U.S. Government securities dealers in New
York City selected by the Independent Investment Banker (each, a "Primary
Treasury Dealer"); PROVIDED, HOWEVER, that if any of the foregoing shall cease
to be a Primary Treasury Dealer, the Company shall substitute therefor another
Primary Treasury Dealer.

     "REFERENCE TREASURY DEALER QUOTATIONS" means, with respect to each
Reference Treasury Dealer and any Redemption Date for the Notes, an average, as
determined by the Trustee, of the bid and asked prices for the Comparable
Treasury Issue for the Notes (expressed in each case as a percentage of its
principal amount) quoted in writing to the Trustee by such Reference Treasury
Dealer at 5:00 p.m., New York City time, on the third business day preceding
such Redemption Date.

                                        8
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     "REGISTRABLE SECURITIES" has the meaning assigned to such term in the
Registration Rights Agreement.

     "REGISTRATION RIGHTS AGREEMENT" means the Registration Rights Agreement,
dated as of March 11, 2003, among the Company and the Initial Purchasers.

     "REGULAR RECORD DATE" has the meaning specified in Section 2.3 hereof.

     "REGULATION S GLOBAL NOTE" means a Global Note in the form of EXHIBIT A
hereto bearing the Global Note Legend and the legend in Section 2.11(f)(i)
hereof and deposited with or on behalf of the Depositary and registered in the
name of the Depositary or its nominee.

     "RESTRICTED DEFINITIVE NOTE" means a Definitive Note bearing the Restricted
Legend.

     "RESTRICTED LEGEND" means the legend initially set forth on the Initial
Notes in the form set forth in Section 2.11(f)(ii).

     "RESTRICTED PERIOD" means the period beginning on the date hereof and
ending on the later of April 27, 2003 and the completion of the distribution of
the Notes by the Initial Purchasers.

     "RULE 144" means Rule 144 promulgated under the Securities Act, any
successor rule or regulation to substantially the same effect or any additional
rule or regulation under the Securities Act that permits transfers of restricted
securities without registration such that the transferee thereof holds
securities that are freely tradeable under the Securities Act.

     "RULE 144A" means Rule 144A promulgated under the Securities Act or any
successor rule or regulation to substantially the same effect.

     "RULE 144A GLOBAL NOTE" means a Global Note in the form of EXHIBIT A hereto
bearing the Global Note Legend and the Restricted Legend and deposited with or
on behalf of, and registered in the name of, the Depositary or its nominee.

     "RULE 903" means Rule 903 promulgated under the Securities Act or any
successor rule or regulation substantially to the same effect.

     "RULE 904" means Rule 904 promulgated under the Securities Act or any
successor rule or regulation substantially to the same effect.

     "SECURED DEBT" means, as of any date, that portion of Total Outstanding
Debt as of that date that is secured by a Lien on properties or other assets of
the Company, any of its Subsidiaries or any of the Partially-Owned Entities.

     "SECURITIES ACT" means the Securities Act of 1933, as amended from time to
time.

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     "SHELF REGISTRATION STATEMENT" has the meaning assigned to such term in the
Registration Rights Agreement.

     "SPECIAL RECORD DATE" has the meaning specified in Section 2.3 hereof.

     "SUBSIDIARY" means, with respect to any Person, a corporation, partnership
association, joint venture, trust, limited liability company or other business
entity which is required to be consolidated with the Company or Boston
Properties in accordance with GAAP.

     "TARGET FILING DATE" has the meaning specified in Section 2.3 hereof.

     "TARGET REGISTRATION DATE" has the meaning specified in Section 2.3 hereof.

     "TOTAL ASSETS" means, with respect to any Incurrence of Debt or Secured
Debt, as of any date, in each case as determined by the Company without
duplication, the sum of: (1) Capitalized Property Value; (2) cash, cash
equivalents and marketable securities of the Company and its Subsidiaries,
determined in accordance with GAAP; (3) with respect to notes receivable and
mortgages, the lesser of (i) the aggregate amount of principal under such note
or mortgage that will be due and payable to the Company or its Subsidiaries and
(ii) the purchase price paid by the Company or its Subsidiaries to acquire such
note or mortgage; (4) with respect to real estate assets which are undeveloped
land, the book value thereof in accordance with GAAP; (5) without duplication,
the cost basis of properties of the Company and its Subsidiaries that are under
development, determined in accordance with GAAP, as of the end of the quarterly
period used for purposes of clause (1) above; (6) without duplication, the
proceeds of the Debt or Secured Debt or the assets to be acquired in exchange
for such proceeds, as the case may be, other than Intercompany Debt, Incurred
from the end of the Latest Completed Quarter prior to the Incurrence of the Debt
or Secured Debt, as the case may be, to the date of determination; and (7) the
Company's and its Subsidiaries' percentage share of Partially-Owned Entities'
assets described in clauses (1), (2), (3), (4), (5) and (6) above.

     "TOTAL OUTSTANDING DEBT" means, as of any date, the sum, without
duplication, of (1) the aggregate principal amount of all outstanding Debt of
the Company as of that date; (2) the aggregate principal amount of all
outstanding Debt of the Company's Subsidiaries, all as of that date; and (3) the
sum of the aggregate principal amount of all Partially-Owned Entity Outstanding
Debt of each of the Partially-Owned Entities multiplied by the Company's
respective Percentage Interest in such Partially-Owned Entity as of that date.

     "TREASURY YIELD" means, with respect to any Redemption Date applicable to
the Notes, the rate per annum equal to the semiannual equivalent yield to
maturity (computed as of the third business day immediately preceding such
Redemption Date) of the Comparable Treasury Issue, assuming a price for the
Comparable Treasury Issue (expressed as a percentage of its principal amount)
equal to the applicable Comparable Treasury Price for such Redemption Date.

                                       10
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     "UNENCUMBERED ASSETS" means, as of any date, in each case as determined by
the Company without duplication, the sum of: (1) Unencumbered Capitalized
Property Value; (2) cash, cash equivalents and marketable securities of the
Company and its Subsidiaries, other than restricted cash, cash equivalents and
marketable securities pledged to secure Debt, determined in accordance with
GAAP; (3) with respect to notes receivable and mortgages, the lesser of (i) the
aggregate amount of principal under such note or mortgage that will be due and
payable to the Company or its Subsidiaries and (ii) the purchase price paid by
the Company or its Subsidiaries to acquire such note or mortgage, except any
notes receivable or mortgages that are serving as collateral for Secured Debt;
(4) with respect to real estate assets which are undeveloped land, the book
value thereof in accordance with GAAP, except any land that is serving as
collateral for Secured Debt; (5) without duplication, the cost basis of
properties of the Company and its Subsidiaries that are under development,
determined in accordance with GAAP, as of the end of the quarterly period used
for purposes of clause (1) above, except any properties that are serving as
collateral for Secured Debt; (6) without duplication, the proceeds of the Debt
or Secured Debt or the assets to be acquired in exchange for such proceeds, as
the case may be, other than Intercompany Debt, Incurred from the end of the
Latest Completed Quarter prior to such date to the date of determination, except
in each case any proceeds or assets that are serving as collateral for Secured
Debt; and (7) the Company's and its Subsidiaries' percentage share, of
Partially-Owned Entities' assets described in clauses (1), (2), (3), (4), (5)
and (6) above. For the avoidance of doubt, cash held by a "qualified
intermediary" in connection with proposed like-kind exchanges pursuant to
Section 1031 of the Code which may be classified as "restricted" for GAAP
purposes shall nonetheless be included in clause (2) above, so long as the
Company or any of its Subsidiaries has the right to (i) direct the qualified
intermediary to return such cash to the Company or such Subsidiary if and when
the Company or such Subsidiary fails to identify or acquire the proposed
like-kind property or at the end of the 180-day replacement period or (ii)
direct the qualified intermediary to use such cash to acquire like-kind
property.

     "UNENCUMBERED CAPITALIZED PROPERTY VALUE" means, as of any date, the sum of
(1) with respect to CBD Properties and non-CBD Properties, in each case that are
not hotel properties, the aggregate of all Unencumbered Property EBITDA for each
such CBD Property and non-CBD Property for the Latest Completed Quarter prior to
such date, annualized (i.e., multiplied by four (4)), and capitalized at the
applicable Capitalization Rate PLUS, (2) with respect to CBD Properties and
non-CBD Properties, in each case that are hotel properties, the aggregate of all
Unencumbered Property EBITDA for each such CBD Property and non-CBD Property for
the most recent four (4) consecutive complete fiscal quarters, capitalized at
the applicable Capitalization Rate; PROVIDED, HOWEVER, that if the value of a
particular property calculated pursuant to clause (1) or (2) above, as
applicable, is less than the undepreciated book value of such property
determined in accordance with GAAP, such undepreciated book value shall be used
in lieu thereof with respect to such property.

     "UNENCUMBERED CONSOLIDATED EBITDA" means, for any period of time,
Consolidated EBITDA for such period of time less any portion thereof
attributable to assets serving as collateral for Secured Debt.

                                       11
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     "UNENCUMBERED PROPERTY EBITDA" means, for any period of time, Property
EBITDA for such period of time less any portion thereof attributable to assets
serving as collateral for Secured Debt.

     "UNRESTRICTED GLOBAL NOTE" means a Global Note (other than a Regulation S
Global Note) in the form of EXHIBIT A hereto that bears the Global Note Legend,
and that is deposited with or on behalf of and registered in the name of the
Depositary, but that does not bear and is not required to bear the Restricted
Legend.

     "UNRESTRICTED DEFINITIVE NOTE" means one or more Definitive Notes that do
not bear and are not required to bear the Restricted Legend.

     "UNSECURED DEBT" means, as of any date, that portion of Total Outstanding
Debt as of that date that is neither Secured Debt nor Contingent Liabilities of
Boston Properties Limited Partnership and Subsidiaries.

     "U.S. PERSON" means a "U.S. Person" as defined in Rule 902(k) under the
Securities Act.

                                   ARTICLE TWO

                                    THE NOTES

     SECTION 2.1.   TITLE OF THE SECURITIES.

     There shall be a series of Securities designated the "5.625% Senior Notes
due 2015" (the "Notes").

     SECTION 2.2.   LIMITATION ON INITIAL AGGREGATE PRINCIPAL AMOUNT; FURTHER
                    ISSUANCES.

     The aggregate principal amount of the Notes initially shall be limited to
$300,000,000. The Company may, from time to time, subject to Section 2.4 of this
Third Supplemental Indenture and applicable law, create and issue additional
Notes under this Third Supplemental Indenture ranking equally and ratably with
the outstanding Notes in all respects (or in all respects except for the payment
of interest accruing prior to the issue date of such additional Notes or except
for the first payment of interest following the issue date of such additional
Notes) without notice to or the consent of the Holders of outstanding Notes. The
initially issued Notes and any additional Notes subsequently issued shall be
consolidated and form a single series with the outstanding Notes for all
purposes of this Third Supplemental Indenture and shall have the same terms as
to status, redemption or otherwise as the outstanding Notes. Any such additional
Notes referred to in this Section 2.2 will be issued under a further
supplemental indenture.

     Nothing contained in this Section 2.2 or elsewhere in this Third
Supplemental Indenture, or in the Notes, is intended to or shall limit execution
by the Company or

                                       12
<Page>

authentication or delivery by the Trustee of Notes under the circumstances
contemplated by Sections 3.03, 3.04, 3.05, 3.06, 9.06, 11.07 and 13.05 of the
Senior Indenture.

     SECTION 2.3.   INTEREST AND INTEREST RATES; MATURITY DATE OF NOTES.

     (a) The Notes shall bear interest at 5.625% per annum from March 18, 2003
or from the immediately preceding Interest Payment Date (as defined below) to
which interest has been paid, payable semi-annually in arrears on April 15 and
October 15 of each year, commencing October 15, 2003 (each, an "Interest Payment
Date"), to the persons (the "Holders") in whose name the applicable Notes are
registered in the Security Register at the close of business 15 calendar days
prior to such Interest Payment Date (I.E., April 1 and October 1, respectively)
(regardless of whether such day is a Business Day, as defined below), as the
case may be (each, a "Regular Record Date"). Interest on the Notes shall be
computed on the basis of a 360-day year of twelve 30-day months. Interest, if
any, not punctually paid or duly provided for on any Interest Payment Date with
respect to a Note ("Defaulted Interest") shall forthwith cease to be payable to
the Holder on the applicable Regular Record Date and may either be paid to the
person in whose name such Note is registered at the close of business on a
special record date (the "Special Record Date") for the payment of such
Defaulted Interest to be fixed by the Trustee, notice of which shall be given to
the Holder of such Note not less than ten days prior to such Special Record
Date, or may be paid at any time in any other lawful manner, as more
particularly described in the Senior Indenture.

     (b) If any Interest Payment Date or Maturity falls on a day that is not a
Business Day, the required payment shall be made on the next Business Day as if
it were made on the date such payment was due and no interest shall accrue on
the amount so payable for the period from and after such Interest Payment Date
or Maturity, as the case may be.

     (c) The Notes shall mature on April 15, 2015.

     (d) In the event that the Exchange Offer Registration Statement or the
Shelf Registration Statement, if required pursuant to the Registration Rights
Agreement, has not been filed on or prior to the date which is 90 days after the
Closing Date (the "Target Filing Date"), the Company shall pay additional
interest (in addition to interest otherwise due on the Notes as provided herein)
("Additional Interest") to each Holder at a per annum rate equal to 0.25% from
the Target Filing Date up to but excluding the date on which the Exchange Offer
Registration Statement or the Shelf Registration Statement, if required pursuant
to the Registration Rights Agreement, is filed. In the event that either (i) the
Exchange Offer has not been completed on or prior to the date which is 210 days
after the Closing Date (the "Target Registration Date") or (ii) the Shelf
Registration Statement, if required pursuant to the Registration Rights
Agreement, is not declared effective by the SEC on or prior to the Target
Registration Date, the Company shall pay Additional Interest to each Holder at a
per annum rate equal to 0.25% from the Target Registration Date up to but
excluding the date on which the Exchange Offer is completed or the Shelf
Registration Statement, if required pursuant to the Registration Rights
Agreement, is declared effective by the SEC. In the event that either (x) the
Exchange

                                       13
<Page>

Offer has not been completed on or prior to the date which is 300 days after the
Closing Date (the "Extended Registration Date") or (y) the Shelf Registration
Statement, if required pursuant to the Registration Rights Agreement, is not
declared effective by the SEC on or prior to the Extended Registration Date, the
Company shall pay Additional Interest to each Holder at a per annum rate equal
to 0.25% from the Extended Registration Date up to but excluding the date on
which the Exchange Offer is completed or the Shelf Registration Statement, if
required pursuant to the Registration Rights Agreement, is declared effective by
the SEC. Notwithstanding the foregoing, (i) no Additional Interest shall be
payable to any Holder of Notes pursuant to this Section 2.3(d) if such Notes
have ceased to be Registrable Securities and (ii) in no event shall the
Additional Interest payable pursuant to this Section 2.3(d) exceed 0.50% per
annum. The Company shall pay such Additional Interest on each Interest Payment
Date, and payment of Additional Interest shall be subject to the terms and
conditions of the Registration Rights Agreement.

     (e) There shall also be payable in respect of each Note all Additional
Interest that may have accrued on such Note for which the Note was exchanged
pursuant to the Exchange Offer, such Additional Interest to be calculated in
accordance with the terms of such Note and payable at the same time and in the
same manner as periodic interest on such Note.

     SECTION 2.4.   LIMITATIONS ON INCURRENCE OF DEBT.

     In addition to the covenants set forth in Article Ten of the Senior
Indenture, there are established pursuant to Section 9.01(2) of the Senior
Indenture the following covenants for the benefit of the Holders of the Notes
and to which the Notes shall be subject:

     (a) The Company shall not, and shall not permit any Subsidiary to, Incur
any Debt, other than Intercompany Debt, if, immediately after giving effect to
the Incurrence of the additional Debt and any other Debt, other than
Intercompany Debt, Incurred since the end of the Latest Completed Quarter prior
to the Incurrence of the additional Debt and the application of the net proceeds
of the additional Debt and such other Debt, Total Outstanding Debt would exceed
60% of Total Assets, in each case determined as of the end of such Latest
Completed Quarter.

     (b) The Company shall not, and shall not permit any Subsidiary to, Incur
any Secured Debt, other than Secured Debt that is also Intercompany Debt, if,
immediately after giving effect to the Incurrence of the additional Secured Debt
and any other Secured Debt, other than Intercompany Debt, Incurred since the end
of the Latest Completed Quarter prior to the Incurrence of the additional
Secured Debt and the application of the net proceeds of the additional Secured
Debt and such other Secured Debt, the aggregate principal amount of all
outstanding Secured Debt is greater than 50% of Total Assets determined as of
the end of such Latest Completed Quarter.

     (c) The Company shall not, and shall not permit any Subsidiary to, Incur
any Debt, other than Intercompany Debt, if, immediately after giving effect to
the Incurrence

                                       14
<Page>

of the additional Debt, the ratio of Annualized Consolidated EBITDA for the
Latest Completed Quarter prior to the Incurrence of the additional Debt, to
Annualized Interest Expense for that quarter would be less than 1.50 to 1.00 on
a pro forma basis after giving effect to the Incurrence of the additional Debt
and to the application of the net proceeds therefrom, and calculated on the
assumption, without duplication, that: (i) the additional Debt and any other
Debt Incurred by the Company, any of its Subsidiaries or any of the
Partially-Owned Entities from the first day of that quarter to the date of
determination, which was outstanding at the date of determination, had been
Incurred at the beginning of that period and continued to be outstanding
throughout that period, and the application of the net proceeds of that Debt,
including to refinance (1) Debt under any revolving credit facility or (2) other
Debt, had occurred at the beginning of that period; (ii) the repayment or
retirement of any other Debt repaid or retired by the Company, any of its
Subsidiaries or any of the Partially-Owned Entities from the first day of that
quarter to the date of determination occurred at the beginning of that period;
PROVIDED that, except as set forth in clause (i) or (iii) of this Section
2.4(c), in determining the amount of Debt so repaid or retired, the amount of
Debt under any revolving credit facility shall be computed based upon the
average daily balance of such Debt during that period; and (iii) in the case of
any acquisition or disposition of any asset or group of assets or the placement
of any assets in service or removal of any assets from service by the Company,
any of its Subsidiaries or any of the Partially-Owned Entities from the first
day of that quarter to the date of determination, including, without limitation,
by merger, or stock or asset purchase or sale, (1) the acquisition, disposition,
placement in service or removal from service had occurred as of the first day of
that period, with the appropriate adjustments to Annualized Interest Expense
with respect to the acquisition, disposition, placement in service or removal
from service being included in that pro forma calculation and (2) the
application of the net proceeds from a disposition to repay or refinance Debt,
including, without limitation, Debt under any revolving credit facility, had
occurred on the first day of that period.

     (d) The Company and its Subsidiaries shall maintain at all times
Unencumbered Assets of not less than 150% of the aggregate principal amount of
all outstanding Unsecured Debt of the Company and its Subsidiaries.

     SECTION 2.5.   OPTIONAL REDEMPTION.

     The Notes shall be redeemable, at the option of the Company, in whole at
any time or in part from time to time, upon not less than 30 days but not more
than 60 days' prior notice mailed to the registered address of each Holder of
Notes to be so redeemed, at a redemption price equal to the greater of (i) 100%
of the principal amount of the Notes to be redeemed or (ii) the sum of (A) the
present values as of the Redemption Date of the remaining scheduled payments of
principal and interest thereon from the Redemption Date to the date of Maturity
(except for currently accrued but unpaid interest) discounted to the Redemption
Date, on a semiannual basis (assuming a 360-day year consisting of twelve 30-day
months), at the applicable Treasury Yield, plus 35 basis points, plus (B)
accrued interest to the Redemption Date.

                                       15
<Page>

     SECTION 2.6.   PLACES OF PAYMENT.

     The Places of Payment where the Notes may be presented or surrendered for
payment, where the Notes may be surrendered for registration of transfer or
exchange and where notices and demands to and upon the Company in respect of the
Notes and the Senior Indenture may be served shall be in the Borough of
Manhattan, The City of New York, and the office or agency for such purpose shall
initially be located at c/o The Bank of New York, 101 Barclay Street-21W, New
York, NY 10286.

     SECTION 2.7.   METHOD OF PAYMENT.

     Payment of the principal of and interest on the Notes shall be made at the
office or agency of the Company maintained for that purpose in the Borough of
Manhattan, The City of New York (which shall initially be an office or agency of
the Trustee), in such coin or currency of the United States of America as at the
time of payment is legal tender for payment of public and private debts;
PROVIDED, HOWEVER, that at the option of the Company, payments of principal and
interest on the Notes (other than payments of principal and interest due at
Maturity) may be made (i) by check mailed to the address of the Person entitled
thereto as such address shall appear in the Security Register or (ii) by wire
transfer to an account maintained by the Person entitled thereto located within
the United States.

     SECTION 2.8.   CURRENCY.

     Principal and interest on the Notes shall be payable in Dollars.

     SECTION 2.9.   REGISTERED SECURITIES; GLOBAL FORM.

     (a)  GENERAL. The Notes shall be issuable and transferable in fully
registered form as Registered Securities, without coupons. The Notes shall
initially be issued in the form of one or more permanent Global Notes, with the
Restricted Legend affixed thereto. The depository for the Notes shall be The
Depository Trust Company (the "Depositary"). The Notes shall not be issuable in
definitive form except as provided in Section 3.05 of the Senior Indenture.

     (b)  RULE 144A GLOBAL NOTES. Notes offered and sold to QIBs pursuant to
Rule 144A shall be issued initially in the form of one or more Rule 144A Global
Notes, which shall be deposited on behalf of the purchasers of the Notes
represented thereby with the Trustee, as custodian for the Depositary, duly
executed by the Company and authenticated by the Trustee. Each Rule 144A Global
Note shall represent such of the outstanding Notes as shall be specified therein
and each shall provide that it shall represent the aggregate principal amount of
outstanding Notes from time to time as conclusively reflected in the books and
records of the Trustee endorsed thereon and that the aggregate principal amount
of outstanding Notes represented thereby may from time to time be reduced or
increased, as appropriate, to reflect exchanges and redemptions. Any change in
the principal amount of a Rule 144A Global Note to reflect the amount of any
increase or decrease in the aggregate principal amount of outstanding Notes
represented thereby shall be made by the Trustee as the custodian for the
Depositary, at

                                       16
<Page>

the direction of the Security Registrar, in accordance with instructions given
by the Holder thereof as required by Section 2.11 hereof.

     (c)  REGULATION S GLOBAL NOTES. Notes offered and sold to QIBs which are
Qualified Persons in reliance on Regulation S shall be issued initially in the
form of one or more Regulation S Global Notes, which shall be deposited on
behalf of the purchasers of the Notes represented thereby with the Trustee, as
custodian for the Depositary, duly executed by the Company and authenticated by
the Trustee. During the Restricted Period, interests in a Regulation S Global
Note must be held through Euroclear or Clearstream, if the holders are
Participants in such systems, or indirectly through organizations that are
Participants in such systems. Following the termination of the Restricted
Period, beneficial interests in a Regulation S Global Note may be held, directly
or indirectly, in the account of any Participant of the Depositary. Each
Regulation S Global Note shall represent such of the outstanding Notes as shall
be specified therein and each shall provide that it shall represent the
aggregate principal amount of outstanding Notes from time to time as
conclusively reflected in the books and records of the Trustee endorsed thereon
and that the aggregate principal amount of outstanding Notes represented thereby
may from time to time be reduced or increased, as appropriate, to reflect
exchanges and redemptions. Any change in the principal amount of a Regulation S
Global Note to reflect the amount of any increase or decrease in the aggregate
principal amount of outstanding Notes represented thereby shall be made by the
Trustee as the custodian for the Depositary, at the direction of the Security
Registrar, in accordance with instructions given by the Holder thereof as
required by Section 2.11 hereof.

     SECTION 2.10.  FORM OF NOTES.

     The Notes shall be substantially in the form attached as EXHIBIT A hereto.

     SECTION 2.11.  TRANSFER AND EXCHANGE.

     (a)  TRANSFER AND EXCHANGE OF GLOBAL NOTES. A Global Note may not be
transferred as a whole except by the Depositary to a nominee of the Depositary,
by a nominee of the Depositary to the Depositary or to another nominee of the
Depositary, or by the Depositary or any such nominee to a successor Depositary
or a nominee of such successor Depositary. All Global Notes shall be exchanged
by the Company for Definitive Notes if (i) the Company delivers to the Trustee
notice from the Depositary stating that it is unwilling or unable to continue to
act as a clearing agency for the Notes or is no longer a clearing agency
registered under the Exchange Act or other applicable law and, in either case, a
successor Depositary is not appointed by the Company within 90 days after the
date of such notice; or (ii) the Company in its sole discretion determines that
the Global Notes (in whole but not in part) should be exchanged for Definitive
Notes and delivers a written notice to such effect to the Trustee; PROVIDED,
that in no event shall a Regulation S Global Note be exchanged by the Company
for Definitive Notes prior to the expiration of the Restricted Period. Upon the
occurrence of any of the preceding events, Definitive Notes shall be issued in
such names as the Depositary shall instruct the Trustee.

                                       17
<Page>

          (b) TRANSFER AND EXCHANGE OF BENEFICIAL INTERESTS IN THE GLOBAL NOTES.
The transfer and exchange of beneficial interests in the Global Notes shall be
effected through the Depositary in accordance with the provisions of the Senior
Indenture and the applicable procedures of the Depositary. Transfers of
beneficial interests in the Global Notes also shall require compliance with
either subparagraph (i) or (ii) below, as applicable, as well as one or more of
the other following subparagraphs, as applicable:

                    (i)    TRANSFER OF BENEFICIAL INTERESTS IN THE SAME OF
GLOBAL NOTE. Beneficial interests in any Rule 144A Global Note may be
transferred to Persons who take delivery thereof in the form of a beneficial
interest in a Rule 144A Global Note in accordance with the transfer restrictions
set forth in the Restricted Legend. Beneficial interests in any Regulation S
Global Note may be transferred to Persons who take delivery thereof in the form
of a beneficial interest in a Regulation S Global Note; PROVIDED, HOWEVER, that
prior to the expiration of the Restricted Period beneficial interests in a
Regulation S Global Note may only be held through Euroclear or Clearstream, if
the holders are Participants in such systems, or indirectly through
organizations that are Participants in such systems. Beneficial interests in any
Unrestricted Global Note may be transferred to Persons who take delivery thereof
in the form of a beneficial interest in an Unrestricted Global Note. No written
orders or instructions shall be required to be delivered to the Security
Registrar to effect the transfers described in this Section 2.11(b)(i).

                    (ii)   ALL OTHER TRANSFERS AND EXCHANGES OF BENEFICIAL
INTERESTS IN GLOBAL NOTES. In connection with all transfers and exchanges of
beneficial interests that are not subject to Section 2.11(b)(i) above, and,
subject to any other requirement in this Section 2.11, the transferor of such
beneficial interest must deliver to the Security Registrar either: (A) (1) a
written order from a Participant or an Indirect Participant given to the
Depositary, Euroclear or Clearstream in accordance with the Applicable
Procedures directing the Depositary to credit or cause to be credited a
beneficial interest in a Global Note of another type in an amount equal to the
beneficial interest to be transferred or exchanged and (2) instructions given in
accordance with the Applicable Procedures containing information regarding the
Participant account to be credited with such increase or (B), subject to Section
2.11(a), (1) a written order from a Participant or an Indirect Participant given
to the Depositary, Euroclear or Clearstream in accordance with the Applicable
Procedures directing the Depositary, Euroclear or Clearstream to cause to be
issued a Definitive Note in an amount equal to the beneficial interest to be
exchanged and (2) instructions given by the Depositary, Euroclear or Clearstream
to the Security Registrar containing information regarding the Person in whose
name such Definitive Note shall be registered to effect the exchange; PROVIDED
that in no event shall Definitive Notes be issued upon the exchange of
beneficial interests in a Regulation S Global Note prior to the expiration of
the Restricted Period. Upon satisfaction of all of the requirements for transfer
or exchange of beneficial interests in Global Notes contained herein and in the
Senior Indenture and the Notes or otherwise applicable under the Securities Act,
the Trustee shall adjust the principal amount of the relevant Global Note(s)
pursuant to Section 2.11(h) hereof.

                                       18
<Page>

                    (iii)  TRANSFER AND EXCHANGE OF BENEFICIAL INTERESTS IN A
RULE 144A GLOBAL NOTE FOR BENEFICIAL INTERESTS IN AN UNRESTRICTED GLOBAL NOTE. A
beneficial interest in a Rule 144A Global Note may be exchanged by any holder
thereof for a beneficial interest in an Unrestricted Global Note or transferred
to a Person who takes delivery thereof in the form of a beneficial interest in
an Unrestricted Global Note if (x) the exchange or transfer complies with the
requirements of Section 2.11(b)(ii) above and (y):

                                (A) such exchange or transfer is effected
          pursuant to the Exchange Offer in accordance with the Registration
          Rights Agreement and the holder of the beneficial interest to be
          transferred, in the case of an exchange, or the transferee, in the
          case of a transfer, certifies in the applicable Letter of Transmittal
          or via the Depositary's book-entry system that it is not (1) a
          broker-dealer, (2) a Person participating in the distribution of the
          Exchange Notes or (3) a Person who is an affiliate (as defined in Rule
          144) of the Company, and such Letter of Transmittal or book-entry
          system certification shall satisfy the requirements of Section
          2.11(b)(ii);

                                (B) such transfer is effected pursuant to the
          Shelf Registration Statement in accordance with the Registration
          Rights Agreement;

                                (C) such transfer is effected by a Participating
          Broker-Dealer pursuant to the Exchange Offer Registration Statement in
          accordance with the Registration Rights Agreement; or

                                (D) a certificate in the form of EXHIBIT B with
          the certification set forth in paragraph 3(d) or 4 thereof is
          completed, and, if the Security Registrar so requests or the
          Applicable Procedures so require, an Opinion of Counsel to the effect
          that the transfer is permitted, and that upon transfer the Notes will
          not be restricted under the Securities Act, is furnished to the
          Security Registrar.

     If any such transfer is effected at a time when an Unrestricted Global Note
has not yet been issued, the Company shall issue and, upon receipt of a Company
Order in accordance with the Senior Indenture, the Trustee shall authenticate
one or more Unrestricted Global Notes in an aggregate principal amount equal to
the aggregate principal amount of beneficial interests so transferred.

                    (iv)   TRANSFER OF BENEFICIAL INTERESTS TO AND FROM
REGULATION S GLOBAL NOTES.

                                (A) TRANSFER OF BENEFICIAL INTERESTS IN A
          REGULATION S GLOBAL NOTE PRIOR TO THE TERMINATION OF THE RESTRICTED
          PERIOD FOR BENEFICIAL INTERESTS IN A RULE 144A GLOBAL NOTE. A
          beneficial interest in any Regulation S Global Note may be transferred
          to a Person who takes

                                       19
<Page>

          delivery thereof in the form of a beneficial interest in a Rule 144A
          Global Note if (x) the transfer complies with the requirements of
          Section 2.11(b)(ii) above and (y) the holder of the beneficial
          interest in the Regulation S Global Note delivers to the Trustee and
          the Security Registrar a certificate in the form of EXHIBIT B hereto
          with the certification set forth in paragraph 1 thereof completed.

                                (B) TRANSFER OF BENEFICIAL INTERESTS IN A
          REGULATION S GLOBAL NOTE FOLLOWING THE TERMINATION OF THE RESTRICTED
          PERIOD FOR BENEFICIAL INTERESTS IN AN UNRESTRICTED GLOBAL NOTE. A
          beneficial interest in any Regulation S Global Note following the
          termination of the Restricted Period may be transferred to a Person
          who takes delivery thereof in the form of a beneficial interest in an
          Unrestricted Global Note if (x) the transfer complies with the
          requirements of Section 2.11(b)(ii) above and (y) the holder of the
          Regulation S Global Note delivers to the Security Registrar a
          certificate in the form of EXHIBIT B hereto with the certification set
          forth in paragraph 3(d) or 4 thereof completed.

                                (C) TRANSFER OF BENEFICIAL INTERESTS IN A RULE
          144A GLOBAL NOTE FOR BENEFICIAL INTERESTS IN A REGULATION S GLOBAL
          NOTE. A beneficial interest in any Rule 144A Global Note may be
          transferred to a Person who takes delivery thereof in the form of a
          beneficial interest in a Regulation S Global Note if (x) the transfer
          complies with the requirements of Section 2.11(b)(ii) above and (y)
          the holder of the beneficial interest in the Rule 144A Global Note
          delivers to the Security Registrar a certificate in the form of
          EXHIBIT B hereto with the certification set forth in paragraph 2
          thereof completed.

     (c)  EXCHANGE OF BENEFICIAL INTERESTS IN GLOBAL NOTES FOR DEFINITIVE NOTES.

                    (i)  BENEFICIAL INTERESTS IN RULE 144A GLOBAL NOTES OR
REGULATION S GLOBAL NOTES TO UNRESTRICTED DEFINITIVE NOTES. Subject to Section
2.11(a), a holder of a beneficial interest in a Rule 144A Global Note or
Regulation S Global Note may exchange such beneficial interest for an
Unrestricted Definitive Note only if such exchange is in accordance with the
Applicable Procedures, and, if the Security Registrar so requests or the
Applicable Procedures so require, an Opinion of Counsel or other certification
to the effect that the exchange is permitted, and that upon exchange the Notes
will not be restricted under the Securities Act, is furnished to the Security
Registrar.

                    (ii)   BENEFICIAL INTERESTS IN UNRESTRICTED GLOBAL NOTES TO
UNRESTRICTED DEFINITIVE NOTES. A holder of a beneficial interest in an
Unrestricted Global Note may, in the circumstances described in Section 2.11(a),
exchange such beneficial interest for an Unrestricted Definitive Note.

     Any exchange pursuant to this Section 2.11(c) shall satisfy the
requirements of Section 2.11(b)(ii). In any such case, the Trustee shall cause
the aggregate principal

                                       20
<Page>

amount of the applicable Global Note to be reduced accordingly pursuant to
Section 2.11(h) hereof, and the Company shall execute and the Trustee, upon
receipt of a Company Order in accordance with the Senior Indenture, shall
authenticate and deliver to the Person designated in the instructions a
Definitive Note in the appropriate principal amount. Any Restricted Definitive
Note issued in exchange for a beneficial interest in a Global Note pursuant to
this Section 2.11(c) shall be registered in such name or names and in such
authorized denomination or denominations as the holder of such beneficial
interest shall instruct the Security Registrar through instructions from the
Depositary and the Participant or Indirect Participant. The Trustee shall
deliver such Definitive Notes to the Persons in whose names such Notes are so
registered.

     (d)  TRANSFER AND EXCHANGE OF DEFINITIVE NOTES FOR DEFINITIVE NOTES. Upon
request by a Holder of Definitive Notes and such Holder's compliance with the
provisions of this Section 2.11(d), the Security Registrar shall register the
transfer or exchange of Definitive Notes. Prior to such registration of transfer
or exchange, the requesting Holder shall present or surrender to the Security
Registrar the Definitive Notes duly endorsed or accompanied by a written
instruction of transfer in form satisfactory to the Security Registrar duly
executed by such Holder or by his attorney, duly authorized in writing. In
addition, the requesting Holder shall provide any additional certifications,
documents and information, as applicable, required pursuant to the following
provisions of this Section 2.11(d).

                    (i)    RESTRICTED DEFINITIVE NOTES TO RESTRICTED
DEFINITIVE NOTES. Any Restricted Definitive Note may be transferred to and
registered in the name of a Person who takes delivery thereof in the form of a
Restricted Definitive Note if the Security Registrar receives the following:

                                (A) if the transfer will be made pursuant to
          Rule 144A, then the transferor must deliver a certificate in the form
          of EXHIBIT B hereto with the certification set forth in paragraph 1
          thereof completed,

                                (B) if the transfer will be made to a Non-U.S.
          Person which is a QIB and a Qualified Person in an offshore
          transaction in accordance with Rule 903 or Rule 904, then the
          transferor must deliver a certificate in the form of EXHIBIT B hereto
          with the certification set forth in paragraph 2 thereof completed; and

                                (C) if the transfer will be made pursuant to any
          other exemption from the registration requirements of the Securities
          Act, then the transferor must deliver an Opinion of Counsel and/or
          other certification in form and substance acceptable to the Security
          Registrar and the Company.

                    (ii)   RESTRICTED DEFINITIVE NOTES TO UNRESTRICTED
DEFINITIVE NOTES. Any Restricted Definitive Note may be exchanged by the Holder
thereof for an Unrestricted Definitive Note or transferred to a Person or
Persons who take delivery thereof in the form of an Unrestricted Definitive Note
if:

                                       21
<Page>

                                (A) such exchange or transfer is effected
          pursuant to the Exchange Offer in accordance with the Registration
          Rights Agreement and the Holder, in the case of an exchange, or the
          transferee, in the case of a transfer, certifies in the applicable
          Letter of Transmittal, that it is not (1) a broker-dealer, (2) a
          Person participating in the distribution of the Exchange Notes or (3)
          a Person who is an affiliate (as defined in Rule 144) of the Company;

                                (B) any such transfer is effected pursuant to
          the Shelf Registration Statement in accordance with the Registration
          Rights Agreement;

                                (C) any such transfer is effected by a
          Participating Broker-Dealer pursuant to the Exchange Offer
          Registration Statement in accordance with the Registration Rights
          Agreement; or

                                (D) a certificate in the form of EXHIBIT B
          hereto with the certification set forth in paragraph 3(d) or 4 thereof
          completed, and, if the Trustee and the Security Registrar so request
          or the Applicable Procedures so require, an Opinion of Counsel to the
          effect that the transfer is permitted, and that upon transfer the
          Notes will not be restricted under the Securities Act, is furnished to
          the Trustee and the Securities Registrar.

                    (iii)  UNRESTRICTED DEFINITIVE NOTES TO UNRESTRICTED
DEFINITIVE NOTES. A Holder of Unrestricted Definitive Notes may transfer such
Notes to a Person who takes delivery thereof in the form of an Unrestricted
Definitive Note. Upon receipt of a request to register such a transfer, the
Security Registrar shall register the Unrestricted Definitive Notes pursuant to
the instructions from the Holder thereof.

     (e)  EXCHANGE OFFER; SHELF REGISTRATION STATEMENT.

                    (i) Upon the occurrence of the Exchange Offer in accordance
with the Registration Rights Agreement, the Company shall issue and, upon
receipt of a Company Order in accordance with the Senior Indenture, the Trustee
shall authenticate (x) one or more Unrestricted Global Notes in an aggregate
principal amount equal to the principal amount of the beneficial interests in
the Rule 144A Global Notes and Regulation S Global Notes tendered for acceptance
by Persons that certify in the applicable Letters of Transmittal that (A) they
are not broker-dealers, (B) they are not participating in a distribution of the
Exchange Notes and (C) they are not affiliates (as defined in Rule 144) of the
Company, and accepted for exchange in the Exchange Offer and (y) Definitive
Notes in an aggregate principal amount equal to the principal amount of the
Restricted Definitive Notes accepted for exchange in the Exchange Offer.
Concurrently with the issuance of such Notes, the Trustee shall cause the
aggregate principal amount of the applicable Rule 144A Global Notes and/or
Regulation S Global Notes to be reduced accordingly, and the Company shall
execute and the Trustee shall, upon receipt of a Company Order in accordance
with the Senior Indenture, authenticate

                                       22
<Page>

and deliver to the Persons designated by the Holders of the Restricted
Definitive Notes so accepted Unrestricted Definitive Notes in the appropriate
principal amount.

                    (ii)   Following the effectiveness of a Shelf Registration
Statement, if any, the Company shall issue and, upon receipt of a Company Order
in accordance with the Senior Indenture, the Trustee shall authenticate from
time to time (x) one or more Unrestricted Global Notes, or, if there shall be at
the time one or more Unrestricted Global Notes outstanding and such increase can
be effected in accordance with the Applicable Procedures, the Trustee shall
increase or cause to be increased the aggregate principal amount thereof, in
each case in an aggregate principal amount equal to the principal amount of the
beneficial interests in the Global Notes sold by Persons that certify as to the
consummation of such sale under the Shelf Registration Statement in a manner
acceptable to the Trustee and the Company and (y) Unrestricted Definitive Notes
in an aggregate principal amount equal to the principal amount of the Restricted
Definitive Notes sold by Persons that certify as to the consummation of such
sale under the Shelf Registration Statement in a manner acceptable to the
Trustee and the Company. Concurrently with the issuance of such Unrestricted
Global Notes, the Trustee shall cause the aggregate principal amount of the
applicable Rule 144A Global Notes and/or the Regulation S Global Notes to be
reduced accordingly, and the Company shall execute and the Trustee shall, upon
receipt of a Company Order in accordance with the Senior Indenture, authenticate
and deliver to the Persons designated by the Holders of Restricted Definitive
Notes so sold Unrestricted Definitive Notes in the appropriate principal amount.

     (f)  LEGENDS.

                    (i)    RESTRICTED LEGEND. Except as otherwise provided in
Section 2.11(g), each Initial Note shall bear the following legend on the face
thereof:

     THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED (THE "SECURITIES ACT"), OR THE SECURITIES LAWS OF ANY STATE OR OTHER
JURISDICTION. NEITHER THIS SECURITY NOR ANY INTEREST OR PARTICIPATION HEREIN MAY
BE REOFFERED, SOLD, ASSIGNED, TRANSFERRED, PLEDGED, ENCUMBERED OR OTHERWISE
DISPOSED OF IN THE ABSENCE OF SUCH REGISTRATION OR UNLESS SUCH TRANSACTION IS
EXEMPT FROM, OR NOT SUBJECT TO, SUCH REGISTRATION. EACH PURCHASER OF THIS NOTE
IS HEREBY NOTIFIED THAT THE SELLER OF THIS NOTE MAY BE RELYING ON THE EXEMPTION
FROM THE PROVISIONS OF SECTION 5 OF THE SECURITIES ACT PROVIDED BY RULE 144A
THEREUNDER.

     THE HOLDER OF THIS SECURITY, BY ITS ACCEPTANCE HEREOF, AGREES ON ITS OWN
BEHALF AND ON BEHALF OF ANY INVESTOR ACCOUNT FOR WHICH IT HAS PURCHASED
SECURITIES, FOR THE BENEFIT OF BOSTON PROPERTIES LIMITED PARTNERSHIP (THE
"ISSUER"), THAT THIS SECURITY MAY BE OFFERED, RESOLD, PLEDGED OR OTHERWISE
TRANSFERRED, ONLY (A) TO THE ISSUER, (B) PURSUANT TO A

                                       23
<Page>

REGISTRATION STATEMENT THAT HAS BEEN DECLARED EFFECTIVE UNDER THE SECURITIES
ACT, (C) FOR SO LONG AS THE SECURITIES ARE ELIGIBLE FOR RESALE PURSUANT TO RULE
144A UNDER THE SECURITIES ACT, TO A PERSON IT REASONABLY BELIEVES IS A
"QUALIFIED INSTITUTIONAL BUYER" AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT
THAT PURCHASES FOR ITS OWN ACCOUNT OR FOR THE ACCOUNT OF A QUALIFIED
INSTITUTIONAL BUYER TO WHOM NOTICE IS GIVEN THAT THE TRANSFER IS BEING MADE IN
RELIANCE ON RULE 144A, (D) TO A QUALIFIED INSTITUTIONAL BUYER WHICH IS A
"QUALIFIED PERSON" WITHIN THE MEANING OF INTERNAL REVENUE CODE SECTION
49(a)(1)(D)(iv) OUTSIDE THE UNITED STATES IN A TRANSACTION COMPLYING WITH THE
PROVISIONS OF RULE 904 UNDER THE SECURITIES ACT, (E) TO AN INSTITUTIONAL
"ACCREDITED INVESTOR" (WITHIN THE MEANING OF RULE 501(a)(1), (2), (3) OR (7)
UNDER THE SECURITIES ACT THAT IS PURCHASING FOR ITS OWN ACCOUNT OR FOR THE
ACCOUNT OF ANOTHER INSTITUTIONAL ACCREDITED INVESTOR, OR (F) UNDER ANY OTHER
AVAILABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT IF
THE PURCHASER REPRESENTS THAT IT IS A "QUALIFIED PERSON" WITHIN THE MEANING OF
INTERNAL REVENUE CODE SECTION 49(a)(1)(D)(iv), AND IN THE CASE OF (A) THROUGH
(F) IN ACCORDANCE WITH ANY APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED
STATES OR ANY OTHER APPLICABLE JURISDICTION. EACH HOLDER WILL NOTIFY ANY
PURCHASER OF THIS NOTE FROM IT OF THE RESALE RESTRICTIONS REFERENCED ABOVE.

THE HOLDER OF THIS SECURITY IS ENTITLED TO THE BENEFITS OF A REGISTRATION RIGHTS
AGREEMENT (AS SUCH TERM IS DEFINED IN THE INDENTURE REFERRED TO ON THE REVERSE
HEREOF) AND, BY ITS ACCEPTANCE HEREOF, AGREES TO BE BOUND BY AND TO COMPLY WITH
THE PROVISIONS OF SUCH REGISTRATION RIGHTS AGREEMENT.

                    (ii)   REGULATION S GLOBAL NOTE LEGEND. The Regulation S
Global Note shall bear the following legend on the face thereof:

DURING THE RESTRICTED PERIOD (AS DEFINED IN THE INDENTURE REFERRED TO ON THE
REVERSE HEREOF), INTERESTS IN THIS REGULATION S GLOBAL NOTE MAY ONLY BE HELD
THROUGH EUROCLEAR AND CLEARSTREAM.

     (g)  (i) If the Company determines (upon the advice of counsel and such
other certifications as the Company may reasonably require) that any Note is
eligible for resale pursuant to Rule 144(k) under the Securities Act (or a
successor provision) and that the Restricted Legend is no longer necessary or
appropriate in order to ensure that subsequent transfers of such Note (or a
beneficial interest therein) are effected in compliance with the Securities Act,
or (ii) after an Initial Note is (x) sold pursuant to an effective registration
statement under the Securities Act, pursuant to the Registration Rights
Agreement or otherwise, or (y) exchanged for an Exchange Note, the Company

                                       24
<Page>

may instruct the Trustee to cancel such Note and issue to the Holder thereof (or
to its transferee) a new Note of like tenor and amount, registered in the name
of the Holder thereof (or its transferee), that does not bear the Restricted
Legend and the Trustee will comply with such instruction.

     (h)  CANCELLATION AND/OR ADJUSTMENT OF GLOBAL NOTES. At such time as all
beneficial interests in a particular Global Note have been exchanged for
Definitive Notes or a particular Global Note has been redeemed, repurchased or
canceled in whole and not in part, each such Global Note shall be returned to or
retained and canceled by the Trustee in accordance with the terms of the Senior
Indenture. At any time prior to such cancellation, if any beneficial interest in
a Global Note is exchanged for or transferred to a Person who will take delivery
thereof in the form of a beneficial interest in another Global Note or for
Definitive Notes, the principal amount of Notes represented by such Global Note
shall be reduced accordingly and an endorsement shall be made on such Global
Note by the Trustee or by the Depositary to reflect such reduction; and if the
beneficial interest is being exchanged for or transferred to a Person who will
take delivery thereof in the form of a beneficial interest in another Global
Note, such other Global Note shall be increased accordingly and an endorsement
shall be made on such Global Note by the Trustee or by the Depositary to reflect
such increase.

     SECTION 2.12.  GENERAL PROVISIONS RELATING TO TRANSFERS AND EXCHANGES.

     (a) The Trustee and the Security Registrar will retain copies of all
certificates, opinions and other documents received in connection with the
transfer or exchange of a Note (or a beneficial interest therein), and the
Company will have the right to inspect and make copies thereof at any reasonable
time upon written notice to the Trustee or the Security Registrar, as the case
may be.

     (b) By its acceptance of any Note bearing the Restricted Legend, each
Holder acknowledges the restrictions on transfer of such Note set forth in this
Third Supplemental Indenture and in the Restricted Legend and agrees that it
will transfer such Note only as provided in this Third Supplemental Indenture.
The Security Registrar shall not register a transfer of any Note unless such
transfer complies with the restrictions on transfer of such Note set forth in
this Third Supplemental Indenture. In connection with any transfer of a Note,
each Holder agrees by its acceptance of such Note to furnish the Security
Registrar or the Company such certifications, legal opinions or other
information as either of them may reasonably require to confirm that such
transfer is being made pursuant to an exemption from, or a transaction not
subject to, the registration requirements of the Securities Act; PROVIDED, that
the Security Registrar shall not be required to determine (but may rely on a
determination made by the Company with respect to) the sufficiency of any such
certifications, legal opinions or other information.

     (c) Each Holder of a Note agrees to indemnify the Company and the Trustee
against any liability that may result from the transfer, exchange or assignment
of such Holder's Note in violation of any provision of this Third Supplemental
Indenture or applicable United States federal or state securities law.

                                       25
<Page>

     (d) The Trustee shall have no obligation or duty to monitor, determine or
inquire as to compliance with any restrictions on transfer imposed under this
Third Supplemental Indenture or under applicable law with respect to any
transfer of any interest in any Note (including any transfers between or among
members of, or Participants or Indirect Participants in, the Depositary or
beneficial owners of interests in any Global Note) other than to require
delivery of such certificates and other documentation or evidence as are
expressly required by, and to do so if and when expressly required by the terms
of, this Third Supplemental Indenture, and to examine the same to determine
substantial compliance as to form with the express requirements hereof.

     SECTION 2.13.  REGISTRAR AND PAYING AGENT.

     The Trustee shall initially serve as Security Registrar and Paying Agent
for the Notes.

     SECTION 2.14.  DEFEASANCE.

     The provisions of Sections 14.02 and 14.03 of the Senior Indenture,
together with the other provisions of Article Fourteen of the Senior Indenture,
shall be applicable to the Notes. The provisions of Section 14.03 of the Senior
Indenture shall apply to the covenants set forth in Sections 2.4 and 2.15 of
this Third Supplemental Indenture and to those covenants specified in Section
14.03 of the Senior Indenture.

     SECTION 2.15.  PROVISION OF FINANCIAL INFORMATION.

     Whether or not the Company is subject to Section 13 or 15(d) of the
Exchange Act, the Company shall, to the extent permitted under the Exchange Act,
file with the Commission the annual reports, quarterly reports and other
documents which the Company would have been required to file with the Commission
pursuant to such Section 13 or 15(d) if the Company were so subject, such
documents to be filed with the Commission on or prior to the respective dates
(the "Required Filing Dates") by which the Company would have been required so
to file such documents if the Company were so subject.

     The Company shall also in any event (x) within 15 days of each Required
Filing Date (i) if the Company is not then subject to Section 13 or 15(d) of the
Exchange Act, transmit by mail to all Holders, as their names and addresses
appear in the Security Register, without cost to such Holders, copies of the
annual reports and quarterly reports which the Company would have been required
to file with the Commission pursuant to Section 13 or 15(d) of the Exchange Act
if the Company were subject to such Sections, and (ii) file with the Trustee
copies of annual reports, quarterly reports and other documents which the
Company would have been required to file with the Commission pursuant to Section
13 or 15(d) of the Exchange Act if the Company were subject to such Sections and
(y) if filing such documents by the Company with the Commission is not permitted
under the Exchange Act, promptly upon written request and payment of the

                                       26
<Page>

reasonable cost of duplication and delivery, supply copies of such documents to
any prospective Holder.

     SECTION 2.16.  WAIVER OF CERTAIN COVENANTS.

     Notwithstanding the provisions of Section 10.09 of the Senior Indenture,
the Company may omit in any particular instance to comply with any term,
provision or condition set forth in Sections 10.04 to 10.08, inclusive, of the
Senior Indenture, with Sections 2.4 and 2.15 of this Third Supplemental
Indenture and with any other term, provision or condition with respect to the
Notes (except any such term, provision or condition which could not be amended
without the consent of all Holders of the Notes), if before or after the time
for such compliance the Holders of at least a majority in principal amount of
all outstanding Notes, by Act of such Holders, either waive such compliance in
such instance or generally waive compliance with such covenant or condition.
Except to the extent so expressly waived, and until such waiver shall become
effective, the obligations of the Company and the duties of the Trustee in
respect of any such term, provision or condition shall remain in full force and
effect.

     SECTION 2.17.  NO SINKING FUND.

     The provisions of Article Twelve of the Senior Indenture shall not be
applicable to the Notes.

     SECTION 2.18.  NO REPAYMENT AT OPTION OF HOLDERS.

     The provisions of Article Thirteen of the Senior Indenture shall not be
applicable to the Notes.

     SECTION 2.19.  DESIGNATION OF CBD PROPERTIES.

     From time to time, the Company may designate one or more additional
properties as CBD Properties by delivering an Officers' Certificate, in
substantially the form attached hereto as EXHIBIT C, to the Trustee (i) setting
forth the name of such property and (ii) certifying that, in the good faith
opinion of such officers, such property is located in the central business
district of a CBD Market. Upon delivery of such Officers' Certificate to the
Trustee, such property shall be a CBD Property for all purposes of this Third
Supplemental Indenture.

                                       27
<Page>

                                  ARTICLE THREE

                            MISCELLANEOUS PROVISIONS

     SECTION 3.1.   RATIFICATION OF SENIOR INDENTURE.

     Except as expressly modified or amended hereby, the Senior Indenture
continues in full force and effect and is in all respects confirmed, ratified
and preserved.

     SECTION 3.2.   GOVERNING LAW.

     This Third Supplemental Indenture and each Note shall be governed by and
construed in accordance with the laws of the State of New York. This Third
Supplemental Indenture is subject to the provisions of the Trust Indenture Act
of 1939, as amended, and shall, to the extent applicable, be governed by such
provisions.

     SECTION 3.3.   COUNTERPARTS.

     This Third Supplemental Indenture may be executed in any number of
counterparts, each of which so executed shall be deemed to be an original, but
all such counterparts shall together constitute but one and the same instrument.

     SECTION 3.4.   TRUSTEE.

     The Trustee makes no representations as to the validity or sufficiency of
this Third Supplemental Indenture. The statements and recitals herein are deemed
to be those of the Company and not of the Trustee.

                                       28
<Page>

     IN WITNESS WHEREOF, the parties hereto have caused this Third Supplemental
Indenture to be duly executed by their respective officers hereunto duly
authorized, all as of the day and year first written above.

                                           BOSTON PROPERTIES LIMITED PARTNERSHIP

                                           By:  Boston Properties, Inc.,
                                                its general partner

                                           By: /s/ Douglas T. Linde
                                              ----------------------------------
                                              Name: Douglas T. Linde
                                              Title: Senior Vice President,
                                                     Chief Financial Officer
                                                     and Treasurer


                                           THE BANK OF NEW YORK, as Trustee

                                           By: /s/ Ming J. Ryan
                                              ----------------------------------
                                              Name: Ming J. Ryan
                                              Title: Vice President

                                       29
<Page>

                                                                      SCHEDULE A

                                 CBD PROPERTIES

         PROPERTY                                        LOCATION
         --------                                        --------
         265 Franklin Street                             Boston, MA
         Prudential Center Tower                         Boston, MA
         101 Huntington Avenue                           Boston, MA
         Prudential Center Retail                        Boston, MA
         Prudential Lord & Taylor                        Boston, MA
         Prudential Saks 5th Avenue                      Boston, MA
         111 Huntington Retail                           Boston, MA
         111 Huntington Avenue                           Boston, MA
         Huntington Retail Parcel                        Boston, MA
         Prudential Center Garage                        Boston, MA
         Cambridge Center One                            Cambridge, MA
         Cambridge Center Three                          Cambridge, MA
         Cambridge Center Eight                          Cambridge, MA
         Cambridge Center Ten                            Cambridge, MA
         Cambridge Center Eleven                         Cambridge, MA
         Cambridge Center Fourteen                       Cambridge, MA
         University Place                                Cambridge, MA
         Cambridge Center North Garage                   Cambridge, MA
         Citigroup Center                                New York, NY
         599 Lexington Avenue                            New York, NY
         280 Park Avenue                                 New York, NY
         5 Times Square                                  New York, NY
         Times Square Tower                              New York, NY
         399 Park Avenue                                 New York, NY
         100 East Pratt Street                           Baltimore, MD
         Riverfront Plaza                                Richmond, VA
         Embarcadero Center One                          San Francisco, CA
         Embarcadero Center Two                          San Francisco, CA
         Embarcadero Center Three                        San Francisco, CA
         Embarcadero Center Four                         San Francisco, CA
         Federal Reserve                                 San Francisco, CA
         West Tower                                      San Francisco, CA
         Metropolitan Square                             Washington, DC
         Market Square North                             Washington, DC
         1301 New York Avenue                            Washington, DC
         Capital Gallery                                 Washington, DC
         500 E Street                                    Washington, DC
         Sumner Square                                   Washington, DC

                                     SC-A-1
<Page>

         PROPERTY                                        LOCATION
         --------                                        --------
         Shaw Pittman Building                           Washington, DC
         901 New York Avenue                             Washington, DC

                                     SC-A-2
<Page>

                                                                      SCHEDULE B

                                   CBD MARKETS

Los Angeles, California
Orange County, California
San Francisco, California
San Jose, California
Denver, Colorado
Washington, D.C.
Miami, Florida
Atlanta, Georgia
Chicago, Illinois
Baltimore, Maryland
Boston, Massachusetts
Cambridge, Massachusetts
Detroit, Michigan
Minneapolis, Minnesota
New York, New York
Portland, Oregon
Philadelphia, Pennsylvania
Dallas, Texas
Houston, Texas
Richmond, Virginia
Seattle, Washington

                                     SC-B-1
<Page>

                                                                       EXHIBIT A

                                  FORM OF NOTE

                               [Face of Security]

     [IF THIS SECURITY IS AN INITIAL NOTE, INSERT: THIS SECURITY HAS NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"),
OR THE SECURITIES LAWS OF ANY STATE OR OTHER JURISDICTION. NEITHER THIS SECURITY
NOR ANY INTEREST OR PARTICIPATION HEREIN MAY BE REOFFERED, SOLD, ASSIGNED,
TRANSFERRED, PLEDGED, ENCUMBERED OR OTHERWISE DISPOSED OF IN THE ABSENCE OF SUCH
REGISTRATION OR UNLESS SUCH TRANSACTION IS EXEMPT FROM, OR NOT SUBJECT TO, SUCH
REGISTRATION. EACH PURCHASER OF THIS NOTE IS HEREBY NOTIFIED THAT THE SELLER OF
THIS NOTE MAY BE RELYING ON THE EXEMPTION FROM THE PROVISIONS OF SECTION 5 OF
THE SECURITIES ACT PROVIDED BY RULE 144A THEREUNDER.

THE HOLDER OF THIS SECURITY, BY ITS ACCEPTANCE HEREOF, AGREES ON ITS OWN BEHALF
AND ON BEHALF OF ANY INVESTOR ACCOUNT FOR WHICH IT HAS PURCHASED SECURITIES, FOR
THE BENEFIT OF BOSTON PROPERTIES LIMITED PARTNERSHIP (THE "ISSUER"), THAT THIS
SECURITY MAY BE OFFERED, RESOLD, PLEDGED OR OTHERWISE TRANSFERRED, ONLY (A) TO
THE ISSUER, (B) PURSUANT TO A REGISTRATION STATEMENT THAT HAS BEEN DECLARED
EFFECTIVE UNDER THE SECURITIES ACT, (C) FOR SO LONG AS THE SECURITIES ARE
ELIGIBLE FOR RESALE PURSUANT TO RULE 144A UNDER THE SECURITIES ACT, TO A PERSON
IT REASONABLY BELIEVES IS A "QUALIFIED INSTITUTIONAL BUYER" AS DEFINED IN RULE
144A UNDER THE SECURITIES ACT THAT PURCHASES FOR ITS OWN ACCOUNT OR FOR THE
ACCOUNT OF A QUALIFIED INSTITUTIONAL BUYER TO WHOM NOTICE IS GIVEN THAT THE
TRANSFER IS BEING MADE IN RELIANCE ON RULE 144A, (D) TO A QUALIFIED
INSTITUTIONAL BUYER WHICH IS A "QUALIFIED PERSON" WITHIN THE MEANING OF INTERNAL
REVENUE CODE SECTION 49(a)(1)(D)(iv) OUTSIDE THE UNITED STATES IN A TRANSACTION
COMPLYING WITH THE PROVISIONS OF RULE 904 UNDER THE SECURITIES ACT, (E) TO AN
INSTITUTIONAL "ACCREDITED INVESTOR" (WITHIN THE MEANING OF RULE 501(a)(1), (2),
(3) OR (7) UNDER THE SECURITIES ACT THAT IS PURCHASING FOR ITS OWN ACCOUNT OR
FOR THE ACCOUNT OF ANOTHER INSTITUTIONAL ACCREDITED INVESTOR, OR (F) UNDER ANY
OTHER AVAILABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES
ACT IF THE PURCHASER REPRESENTS THAT IT IS A "QUALIFIED PERSON" WITHIN THE
MEANING OF INTERNAL REVENUE CODE SECTION 49(a)(1)(D)(iv), AND IN THE CASE OF (A)
THROUGH (F) IN ACCORDANCE WITH ANY APPLICABLE SECURITIES LAWS OF ANY STATE OF
THE UNITED STATES OR ANY OTHER APPLICABLE JURISDICTION.

                                       A-1
<Page>

EACH HOLDER WILL NOTIFY ANY PURCHASER OF THIS NOTE FROM IT OF THE RESALE
RESTRICTIONS REFERENCED ABOVE.

THE HOLDER OF THIS SECURITY IS ENTITLED TO THE BENEFITS OF A REGISTRATION RIGHTS
AGREEMENT (AS SUCH TERM IS DEFINED IN THE INDENTURE REFERRED TO ON THE REVERSE
HEREOF) AND, BY ITS ACCEPTANCE HEREOF, AGREES TO BE BOUND BY AND TO COMPLY WITH
THE PROVISIONS OF SUCH REGISTRATION RIGHTS AGREEMENT.]

[IF THIS SECURITY IS A REGULATION S GLOBAL NOTE, INSERT: DURING THE RESTRICTED
PERIOD (AS DEFINED IN THE INDENTURE REFERRED TO ON THE REVERSE HEREOF),
INTERESTS IN THIS REGULATION S GLOBAL NOTE MAY ONLY BE HELD THROUGH EUROCLEAR
AND CLEARSTREAM.]

[IF THE HOLDER OF THIS SECURITY (AS INDICATED BELOW) IS THE DEPOSITORY TRUST
COMPANY ("DTC") OR A NOMINEE OF DTC, INSERT: UNLESS THIS SECURITY IS PRESENTED
BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK
CORPORATION ("DTC"), TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER,
EXCHANGE OR PAYMENT, AND SUCH SECURITY ISSUED IS REGISTERED IN THE NAME OF CEDE
& CO., OR IN SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC
(AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED
BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE
HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL, INASMUCH AS THE
REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

UNLESS AND UNTIL THIS SECURITY IS EXCHANGED IN WHOLE OR IN PART FOR SECURITIES
IN CERTIFICATED FORM, THIS SECURITY MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY
DTC TO A NOMINEE THEREOF OR BY A NOMINEE THEREOF TO DTC OR ANOTHER NOMINEE OF
DTC OR BY DTC OR ANY SUCH NOMINEE TO A SUCCESSOR OF DTC OR A NOMINEE OF SUCH
SUCCESSOR.]

                      BOSTON PROPERTIES LIMITED PARTNERSHIP
                          5.625% Senior Notes due 2015

No. ________                                                      $___________
CUSIP No. ________

     BOSTON PROPERTIES LIMITED PARTNERSHIP, a Delaware limited partnership
(herein referred to as the "Company," which term includes any successor
corporation under the Indenture referred to on the reverse hereof), for value
received, hereby promises to pay to ________________________ or registered
assigns the principal sum of _______ Dollars on April 15, 2015 (the "Stated
Maturity Date") or earlier at the option of the Company as provided herein (the
"Redemption Date") and to pay interest thereon from March 18, 2003 or from the
most recent Interest Payment Date to which interest has been paid or duly
provided for, semi-annually on April 15 and

                                       A-2
<Page>

October 15 in each year (each, an "Interest Payment Date"), commencing October
15, 2003, at the rate of 5.625% per annum, until the principal hereof is paid or
duly provided for. The interest so payable, and punctually paid or duly provided
for, on any Interest Payment Date will, as provided in such Indenture, be paid
to the Holder in whose name this Security (or one or more Predecessor
Securities) is registered at the close of business on the Regular Record Date
for such interest, which shall be the April 1 or October 1 (whether or not a
Business Day), as the case may be, next preceding such Interest Payment Date at
the office or agency of the Company maintained for such purpose; PROVIDED,
HOWEVER, that such interest may be paid, at the Company's option, by mailing a
check to such Holder at its registered address or by transfer of funds to an
account maintained by such Holder within the United States. Any such interest
not so punctually paid or duly provided for shall forthwith cease to be payable
to the Holder on such Regular Record Date, and may be paid to the Holder in
whose name this Security (or one or more Predecessor Securities) is registered
at the close of business on a Special Record Date for the payment of such
Defaulted Interest to be fixed by the Trustee, notice whereof shall be given to
Holders of Securities of this series not less than 10 days prior to such Special
Record Date, or may be paid at any time in any other lawful manner not
inconsistent with the requirements of any securities exchange on which the
Securities of this series may be listed, and upon such notice as may be required
by such exchange, all as more fully provided in the Indenture. Interest will be
computed on the basis of a 360-day year of twelve 30-day months.

     The principal of this Security payable on the Stated Maturity Date or the
principal of, premium or Make-Whole Amount, if any, and, if the Redemption Date
is not an Interest Payment Date, interest on this Security payable on the
Redemption Date, will be paid against presentation of this Security at the
office or agency of the Company maintained for that purpose in the Borough of
Manhattan, The City of New York, in such coin or currency of the United States
of America as at the time of payment is legal tender for the payment of public
and private debts.

     Interest payable on this Security on any Interest Payment Date and on the
Stated Maturity Date or Redemption Date, as the case may be, will include
interest accrued from and including the next preceding Interest Payment Date in
respect of which interest has been paid or duly provided for (or from and
including March 18, 2003, if no interest has been paid on this Security) to but
excluding such Interest Payment Date or the Stated Maturity Date or Redemption
Date, as the case may be. If any Interest Payment Date or the Stated Maturity
Date or Redemption Date falls on a day that is not a Business Day, as defined
below, principal, premium or Make-Whole Amount, if any, and/or interest payable
with respect to such Interest Payment Date or Stated Maturity Date or Redemption
Date, as the case may be, will be paid on the next succeeding Business Day with
the same force and effect as if it were paid on the date such payment was due,
and no interest shall accrue on the amount so payable for the period from and
after such Interest Payment Date or Stated Maturity Date or Redemption Date, as
the case may be. "Business Day" means any day, other than a Saturday or Sunday,
that is neither a legal holiday nor a day on which banking institutions in The
City of New York are required or authorized by law, regulation or executive
order to close.

                                       A-3
<Page>

     [IF THIS SECURITY IS A GLOBAL NOTE, INSERT: All payments of principal,
premium or Make-Whole Amount, if any, and interest in respect of this Security
will be made by the Company in immediately available funds.]

     Reference is hereby made to the further provisions of this Security set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

     Unless the Certificate of Authentication hereon has been executed by the
Trustee by manual signature of one of its authorized signatories, this Security
shall not be entitled to any benefit under the Indenture, or be valid or
obligatory for any purpose.

                                       A-4
<Page>

     IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its facsimile corporate seal.

Dated:
     --------------------------

                                           BOSTON PROPERTIES LIMITED PARTNERSHIP

                                           By:  Boston Properties, Inc., its
                                           general partner


                                                By:
                                                   -----------------------------
                                                Name:
                                                Title:

Attest:


-------------------------------
Secretary

                          CERTIFICATE OF AUTHENTICATION

     This is one of the Securities of the series designated therein referred to
in the within-mentioned Indenture.

                                           THE BANK OF NEW YORK,
                                           as Trustee


Dated:                                     By:
     --------------------------                ---------------------------------
                                                    Authorized Signatory

                                       A-5
<Page>

                              [Reverse of Security]

                      BOSTON PROPERTIES LIMITED PARTNERSHIP

     This Security is one of a duly authorized issue of securities of the
Company (herein called the "Securities"), issued and to be issued in one or more
series under an Indenture, dated as of December 13, 2002, as supplemented by
Supplemental Indenture No. 3, dated as of March 18, 2003 (as so supplemented,
herein called the "Indenture"), each between the Company and The Bank of New
York, as Trustee (herein called the "Trustee," which term includes any successor
trustee under the Indenture with respect to the series of which this Security is
a part), to which Indenture and all indentures supplemental thereto reference is
hereby made for a statement of the respective rights, limitations of rights,
duties and immunities thereunder of the Company, the Trustee and the Holders of
the Securities, and of the terms upon which the Securities are, and are to be,
authenticated and delivered. The aggregate principal amount of the Securities to
be issued under such series is initially limited to $300,000,000 (except for
Securities authenticated and delivered upon transfer of, or in exchange for, or
in lieu of other Securities). All terms used in this Security which are defined
in the Indenture shall have the meanings assigned to them in the Indenture.

     If an Event of Default, as defined in the Indenture, with respect to the
Securities shall occur and be continuing, the principal of the Securities of
this series may be declared due and payable in the manner and with the effect
provided in the Indenture.

     The Securities are subject to redemption, at the option of the Company, in
whole at any time or in part from time to time at a redemption price equal to
the greater of (i) 100% of the principal amount of the Securities to be redeemed
or (ii) the sum of (A) the present values of the remaining scheduled payments of
principal and interest thereon from the Redemption Date to the date of Maturity
(except for currently accrued but unpaid interest) discounted to the Redemption
Date, on a semiannual basis (assuming a 360-day year consisting of twelve 30-day
months), at the applicable Treasury Yield, plus 35 basis points, plus (B)
accrued interest to the Redemption Date.

     Notice of redemption will be given by mail to Holders of Securities, not
less than 30 nor more than 60 days prior to the Redemption Date, all as provided
in the Indenture.

     In the event of redemption of this Security in part only, a new Security or
Securities for the unredeemed portion hereof shall be issued in the name of the
Holder hereof upon the cancellation hereof.

     In the event that the Exchange Offer Registration Statement or the Shelf
Registration Statement, if required pursuant to the Registration Rights
Agreement, has not been filed on or prior to the date which is 90 days after the
Closing Date (the "Target Filing Date"), the Company shall pay additional
interest (in addition to interest otherwise due on the Notes as provided herein)
("Additional Interest") to each Holder at a per annum rate equal to 0.25% from
the Target Filing Date up to but excluding the date on which the Exchange Offer
Registration Statement or the Shelf Registration Statement, if

                                       A-6
<Page>

required pursuant to the Registration Rights Agreement, is filed. In the event
that either (i) the Exchange Offer has not been completed on or prior to the
date which is 210 days after the Closing Date (the "Target Registration Date")
or (ii) the Shelf Registration Statement, if required pursuant to the
Registration Rights Agreement, is not declared effective by the SEC on or prior
to the Target Registration Date, the Company shall pay Additional Interest to
each Holder at a per annum rate equal to 0.25% from the Target Registration Date
up to but excluding the date on which the Exchange Offer is completed or the
Shelf Registration Statement, if required pursuant to the Registration Rights
Agreement, is declared effective by the SEC. In the event that either (x) the
Exchange Offer has not been completed on or prior to the date which is 300 days
after the Closing Date (the "Extended Registration Date") or (y) the Shelf
Registration Statement, if required pursuant to the Registration Rights
Agreement, is not declared effective by the SEC on or prior to the Extended
Registration Date, the Company shall pay Additional Interest to each Holder at a
per annum rate equal to 0.25% from the Extended Registration Date up to but
excluding the date on which the Exchange Offer is completed or the Shelf
Registration Statement, if required pursuant to the Registration Rights
Agreement, is declared effective by the SEC. Notwithstanding the foregoing, (i)
no Additional Interest shall be payable to any Holder of Securities pursuant to
this provision if such Securities have ceased to be Registrable Securities and
(ii) in no event shall the Additional Interest payable pursuant to this
provision exceed 0.50% per annum. The Company shall pay such Additional Interest
on each Interest Payment Date, and payment of Additional Interest shall be
subject to the terms and conditions of the Registration Rights Agreement.

     The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders of the Securities under the Indenture at
any time by the Company and the Trustee with the consent of the Holders of not
less than a majority of the aggregate principal amount of all Securities issued
under the Indenture at the time Outstanding and affected thereby. The Indenture
also contains provisions permitting the Holders of not less than a majority of
the aggregate principal amount of the Outstanding Securities, on behalf of the
Holders of all such Securities, to waive compliance by the Company with certain
provisions of the Indenture. Furthermore, provisions in the Indenture permit the
Holders of not less than a majority of the aggregate principal amount, in
certain instances, of the Outstanding Securities of any series to waive, on
behalf of all of the Holders of Securities of such series, certain past defaults
under the Indenture and their consequences. Any such consent or waiver by the
Holder of this Security shall be conclusive and binding upon such Holder and
upon all future Holders of this Security and other Securities issued upon the
registration of transfer hereof or in exchange herefor or in lieu hereof,
whether or not notation of such consent or waiver is made upon this Security.

     No reference herein to the Indenture and no provision of this Security or
of the Indenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of (and premium or Make-Whole
Amount, if any) and interest on this Security at the times, places and rate, and
in the coin or currency, herein prescribed.

                                       A-7
<Page>

     As provided in the Indenture and subject to certain limitations therein set
forth, the transfer of this Security is registrable in the Security Register of
the Company upon surrender of this Security for registration of transfer at the
office or agency of the Company in any place where the principal of (and premium
or Make-Whole Amount, if any) and interest on this Security are payable, duly
endorsed by, or accompanied by a written instrument of transfer in form
satisfactory to the Company and the Security Registrar duly executed by, the
Holder hereof or by his attorney duly authorized in writing, and thereupon one
or more new Securities, of authorized denominations and for the same aggregate
principal amount, will be issued to the designated transferee or transferees.

     As provided in the Indenture and subject to certain limitations therein set
forth, this Security is exchangeable for a like aggregate principal amount of
Securities of different authorized denominations but otherwise having the same
terms and conditions, as requested by the Holder hereof surrendering the same.

     The Securities of this series are issuable only in registered form without
coupons in denominations of $1,000 and any integral multiple thereof.

     No service charge shall be made for any such registration of transfer or
exchange, but the Company may require payment of a sum sufficient to cover any
tax or other governmental charge payable in connection therewith.

     Prior to due presentment of this Security for registration of transfer, the
Company, the Trustee and any agent of the Company or the Trustee may treat the
Person in whose name this Security is registered as the owner hereof for all
purposes, whether or not this Security be overdue, and neither the Company, the
Trustee nor any such agent shall be affected by notice to the contrary.

     No recourse shall be had for the payment of the principal of or premium or
Make-Whole Amount, if any, or the interest on this Security, or for any claim
based hereon, or otherwise in respect hereof, or based on or in respect of the
Indenture or any indenture supplemental thereto, against any past, present or
future stockholder, employee, officer or director, as such, of Boston Properties
or of any successor, either directly or through Boston Properties or any
successor, whether by virtue of any constitution, statute or rule of law or by
the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

     The Indenture and the Securities shall be governed by and construed in
accordance with the laws of the State of New York applicable to agreements made
and to be performed entirely in such State.

                                      A-8
<Page>

                                 ASSIGNMENT FORM

To assign this Security, fill in the form below: (I) or (we) assign and transfer
this Security to


--------------------------------------------------------------------------------
                  (Insert assignee's soc. sec. or tax I.D. no.)


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


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


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


--------------------------------------------------------------------------------
(Print or type assignee's name, address and zip code

and irrevocably appoint_________________________________________________________
to transfer this Security on the books of the Company. The agent may substitute
another to act for him.


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

Date:                                      Your Signature:
    -----------------------                               ----------------------
                                           (Sign exactly as your name appears on
                                           the face of this Security)

                                           Tax Identification No:
                                                                 ---------------

                                           SIGNATURE GUARANTEE:

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

                                           Signatures must be guaranteed by an
                                           "eligible guarantor institution"
                                           meeting the requirements of the
                                           Security Registrar, which
                                           requirements include membership or
                                           participation in the Security
                                           Transfer Agent Medallion Program
                                           ("STAMP") or such other "signature
                                           guarantee program" as may be
                                           determined by the Security Registrar
                                           in addition to, or in substitution
                                           for, STAMP, all in accordance with
                                           the Securities Exchange Act of 1934,
                                           as amended.

                                       A-9
<Page>

             SCHEDULE OF EXCHANGES OF INTERESTS IN THE GLOBAL NOTE1

     The following exchanges of a part of this Global Note for an interest in
another Global Note or for a Definitive Note, or exchanges of a part of another
Global Note or Definitive Note for an interest in this Global Note, have been
made:

<Table>
<Caption>
                                                                       Principal amount of
                           Amount of decrease    Amount of increase      this Global Note         Signature of
                              in principal          in principal          following such       authorized officer
                             amount of this        amount of this            decrease             of Trustee or
   Date of Exchange           Global Note           Global Note            (or increase)          Note Custodian
-----------------------  ---------------------  ---------------------  ---------------------- ----------------------
<S>                      <C>                    <C>                    <C>                    <C>

</Table>

                                      A-10
<Page>

                                                                       EXHIBIT B

                                     FORM OF
                              TRANSFER CERTIFICATE

Boston Properties Limited Partnership
800 Boylston Street
Suite 400
Boston, Massachusetts 02199
Attention:[______________]

The Bank of New York
101 Barclay Street-21W
New York, New York 10286
Attention:[______________]

                  Re:   5.625% SENIOR NOTES DUE 2015

                  Reference is hereby made to Supplemental Indenture No. 3,
dated as of March 18, 2003 (the "Third Supplemental Indenture"), between Boston
Properties Limited Partnership (the "Company") and The Bank of New York, as
trustee. Capitalized terms used but not defined herein shall have the meanings
given to them in the Third Supplemental Indenture.

                  _______________, (the "Transferor") owns and proposes to
transfer the Note[s] or interest in such Note[s] specified in Annex A hereto, in
the principal amount of $__________________ in such Note[s] or interests (the
"Transfer"), to _______________ (the "Transferee"), as further specified in
Annex A hereto. In connection with the Transfer, the Transferor hereby certifies
that:

                             [CHECK ALL THAT APPLY]

(1)  - CHECK IF TRANSFEREE WILL TAKE DELIVERY OF A BENEFICIAL INTEREST IN A 144A
GLOBAL NOTE OR A RESTRICTED DEFINITIVE NOTE PURSUANT TO RULE 144A. The Transfer
is being effected pursuant to and in accordance with Rule 144A under the United
States Securities Act of 1933, as amended (the "Securities Act"), and,
accordingly, the Transferor hereby further certifies that the beneficial
interest or Restricted Definitive Note is being transferred to a Person that the
Transferor reasonably believed and believes is purchasing the beneficial
interest or Restricted Definitive Note for its own account, or for one or more
accounts with respect to which such Person exercises sole investment discretion,
and such Person and each such account is a "qualified institutional buyer"
within the meaning of Rule 144A in a transaction meeting the requirements of
Rule 144A and such Transfer is in compliance with any applicable blue sky
securities laws of any state of the United States. Upon consummation of the
proposed Transfer in accordance with the terms of the Third Supplemental
Indenture, the transferred beneficial interest or Restricted Definitive Note
will be subject to the restrictions on transfer enumerated in the Restricted
Legend printed on the 144A Global Note and/or the Restricted Definitive Note and
in the Third Supplemental Indenture and under the Securities Act.

(2)  - CHECK IF TRANSFEREE WILL TAKE DELIVERY OF A BENEFICIAL INTEREST IN A
REGULATION S GLOBAL NOTE OR A RESTRICTED DEFINITIVE NOTE PURSUANT TO REGULATION
S. The Transfer is being effected pursuant to and in accordance with Rule 903 or
Rule 904 under the Securities Act and,

                                       B-1
<Page>

accordingly, the Transferor hereby further certifies that (i) the Transfer is
not being made to a person in the United States and (x) at the time the buy
order was originated, the Transferee was outside the United States or such
Transferor and any Person acting on its behalf reasonably believed and believes
that the Transferee was outside the United States or (y) the transaction was
executed in, on or through the facilities of a designated offshore securities
market and neither such Transferor nor any Person acting on its behalf knows
that the transaction was prearranged with a buyer in the United States, (ii) no
directed selling efforts have been made in contravention of the requirements of
Rule 903(b) or Rule 904(b) of Regulation S under the Securities Act, (iii) the
transaction is not part of a plan or scheme to evade the registration
requirements of the Securities Act, (iv) the transfer is being made to a person
which is a QIB and a Qualified Person and (v) if the proposed transfer is being
made prior to the expiration of the Restricted Period, the transfer is not being
made to a U.S. Person or for the account or benefit of a U.S. Person (other than
one of the Initial Purchasers). Upon consummation of the proposed transfer in
accordance with the terms of the Third Supplemental Indenture, the transferred
beneficial interest or Restricted Definitive Note will be subject to the
restrictions on Transfer enumerated in the Restricted Legend printed on the
Regulation S Global Note and/or the Restricted Definitive Note and in the Third
Supplemental Indenture and under the Securities Act.

(3)  - CHECK AND COMPLETE IF TRANSFEREE WILL TAKE DELIVERY OF A DEFINITIVE NOTE
PURSUANT TO ANY PROVISION OF THE SECURITIES ACT OTHER THAN RULE 144A OR
REGULATION S. The Transfer is being effected in compliance with the transfer
restrictions applicable to beneficial interests in Restricted Global Notes and
Restricted Definitive Notes and pursuant to and in accordance with the
Securities Act and any applicable blue sky securities laws of any state of the
United States, and accordingly the Transferor hereby further certifies that
(check one):

          (a) - such Transfer is being effected pursuant to and in accordance
with Rule 144 under the Securities Act;

          (b) - such Transfer is being effected to the Company or a subsidiary
thereof;

          (c) - such Transfer is being effected to an institutional "accredited
investor" (within the meaning of Rule 501(a)(1), (2), (3) or (7) under the
Securities Act); or

          (d) - such Transfer is being effected pursuant to an effective
registration statement under the Securities Act and in compliance with the
prospectus delivery requirements of the Securities Act.

                                       B-2
<Page>

(4)  - CHECK IF TRANSFEREE WILL TAKE DELIVERY OF A BENEFICIAL INTEREST IN AN
UNRESTRICTED GLOBAL NOTE OR OF AN UNRESTRICTED DEFINITIVE NOTE.

          (a) - CHECK IF TRANSFER IS PURSUANT TO RULE 144. (i) The Transfer is
being effected pursuant to and in accordance with Rule 144 under the Securities
Act and in compliance with the transfer restrictions contained in the Third
Supplemental Indenture and any applicable blue sky securities laws of any state
of the United States and (ii) the restrictions on transfer contained in the
Third Supplemental Indenture and the Restricted Legend are not required in order
to maintain compliance with the Securities Act. Upon consummation of the
proposed Transfer in accordance with the terms of the Third Supplemental
Indenture, the transferred beneficial interest or Definitive Note will no longer
be subject to the restrictions on transfer enumerated in the Restricted Legend
printed on the Restricted Global Notes, on Restricted Definitive Notes and in
the Third Supplemental Indenture.

          (b) - CHECK IF TRANSFER IS PURSUANT TO REGULATION S. (i) The Transfer
is being effected pursuant to and in accordance with Rule 903 or Rule 904 under
the Securities Act and in compliance with the transfer restrictions contained in
the Third Supplemental Indenture and any applicable blue sky securities laws of
any state of the United States and (ii) the restrictions on transfer contained
in the Third Supplemental Indenture and the Restricted Legend are not required
in order to maintain compliance with the Securities Act. Upon consummation of
the proposed Transfer in accordance with the terms of the Third Supplemental
Indenture, the transferred beneficial interest or Definitive Note will no longer
be subject to the restrictions on transfer enumerated in the Restricted Legend
printed on the Restricted Global Notes, on Restricted Definitive Notes and in
the Third Supplemental Indenture.

          (c) - CHECK IF TRANSFER IS PURSUANT TO OTHER EXEMPTION. (i) The
Transfer is being effected pursuant to and in compliance with an exemption from
the registration requirements of the Securities Act other than Rule 144, Rule
903 or Rule 904 and in compliance with the transfer restrictions contained in
the Third Supplemental Indenture and any applicable blue sky securities laws of
any State of the United States and (ii) the restrictions on transfer contained
in the Third Supplemental Indenture and the Restricted Legend are not required
in order to maintain compliance with the Securities Act. Upon consummation of
the proposed Transfer in accordance with the terms of the Third Supplemental
Indenture, the transferred beneficial interest or Definitive Note will not be
subject to the restrictions on transfer enumerated in the Restricted Legend
printed on the Restricted Global Notes or Restricted Definitive Notes and in the
Third Supplemental Indenture.

          This certificate and the statements contained herein are made for the
benefit of the Trustee and the Company.

                                                   [Insert Name of Transferor]

                                                   By:
                                                      --------------------------
                                                      Name:
                                                      Title:

Dated:
       --------------------

                                       B-3
<Page>

                                                                         ANNEX A

1.   The Transferor owns and proposes to transfer the following:

                            [CHECK ONE OF (a) OR (b)]

     (a)  - a beneficial interest in the:

          (i)   - 144A Global Note (CUSIP __________), or

          (ii)  - Regulation S Global Note (CUSIP __________); or

     (b)  - a Restricted Definitive Note.

2. After the Transfer the Transferee will hold:

                                   [CHECK ONE]

     (a)  - a beneficial interest in the:

          (i)   -  144A Global Note (CUSIP __________), or

          (ii)  - Regulation S Global Note (CUSIP __________); or

          (iii) - Unrestricted Global Note (CUSIP __________); or

     (b)  - a Restricted Definitive Note; or

     (c)  - an Unrestricted Definitive Note,

          in accordance with the terms of the Third Supplemental
          Indenture.

                                    ANNEX A-1
<Page>

                                                                       EXHIBIT C

                                     FORM OF
                              OFFICERS' CERTIFICATE

     Reference is made to Supplemental Indenture No. 3, dated as of March 18,
2003 (the "Third Supplemental Indenture"), between Boston Properties Limited
Partnership (the "Company") and The Bank of New York, as trustee. Pursuant to
Section 2.19 of the Third Supplemental Indenture, each of the undersigned
officers of Boston Properties, Inc., the general partner of the Company, hereby
certifies that in his good faith judgment the properties listed on the schedule
attached hereto are located in a central business district of a CBD Market (as
such term is defined in the Third Supplemental Indenture). In accordance with
Section 2.19 of the Third Supplemental Indenture, each such property listed on
such schedule shall be a CBD Property for all purposes of the Third Supplemental
Indenture.

                                                   -----------------------------
                                                   Name:
                                                   Title:

                                                   -----------------------------
                                                   Name:
                                                   Title:

Dated:
     -----------------

                                       C-1