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                                                                     Exhibit 4.5




                  VOTING AGREEMENT, dated as of February 14, 2000, by and among
Lexent Inc. (the "Company"), Hugh J. O'Kane, Jr. ("Hugh O'Kane"), and Kevin M.
O'Kane ("Kevin O'Kane" and together with Hugh O'Kane, the "Stockholders").

                  WHEREAS, Hugh O'Kane and Kevin O'Kane are stockholders of the
Company and wish to provide for the continuity and stability of the policy and
management of the Company in the event that either dies; and

                  WHEREAS, Hugh O'Kane is about to establish the Hugh J. O'Kane,
Jr. 2000 Grantor Retained Annuity Trust (the "GRAT Trust") and the Hugh J.
O'Kane, Jr. 2000 Remainder Trust (the "Remainder Trust" and together with the
GRAT Trust, the "Trusts"), and he is initially going to transfer 1,400,000
shares of Common Stock, $.001 par value, of the Company ("Common Stock"), to the
GRAT Trust, which shares he wishes to be and remain subject to the provisions of
this Voting Agreement;

                  NOW, THEREFORE, in consideration of the premises and mutual
covenants herein contained, and other good and valuable consideration, the
parties hereto agree as follows:

                  SECTION 1.  Voting Agreement; Proxies.

                  (a) Hugh O'Kane agrees that in the event of his death, Kevin
O'Kane shall have, for a period of three (3) years from such date (the "HOK
Voting Period"), the unilateral right to vote all shares of capital stock (and
other voting interests) of the Company (and any other shares of capital stock or
other equity interests of any successor entity or as may result from any
reorganization, reclassification, merger, or similar event, as the case may be
(such shares and interests are collectively referred to herein as the "HOK
Voting Shares")) owned of record or beneficially by him at his death, and,
accordingly, the undersigned Hugh O'Kane hereby irrevocably appoints Kevin
O'Kane as his lawful proxy agent to vote any or all of the aforementioned HOK
Voting Shares during the HOK Voting Period at any and all general or special
meetings of stockholders, whether in person, by proxy or by written consent.

                  Hugh O'Kane expressly intends that this Agreement shall be
binding upon his heirs, beneficiaries, legatees, executors, trustees and legal
guardians. Hugh O'Kane acknowledges that the Common Stock being transferred by
him to the GRAT Trust (and thereafter to the Remainder Trust) is and shall
remain subject to this Agreement.

                  (b) Kevin O'Kane agrees that in the event of his death, Hugh
O'Kane shall have, for a period of three (3) years from such date (the "KOK
Voting Period"), the unilateral right to vote all shares of capital stock (and
other voting interests) of the Company (and any other shares of capital stock or
other equity interests of any successor entity or as may result from any
reorganization, reclassification, merger, or similar event, as the case may be
(such shares and interests are collectively referred to herein as the "KOK
Voting Shares," and together with the HOK Voting Shares, as the "Voting
Shares")) owned of record or beneficially by him at his
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death, and, accordingly, the undersigned Kevin O'Kane hereby irrevocably
appoints Hugh O'Kane as his lawful proxy agent to vote any or all of the
aforementioned KOK Voting Shares during the KOK Voting Period at any and all
general or special meetings of stockholders, whether in person, by proxy or by
written consent. Kevin O'Kane expressly intends that this Agreement shall be
binding upon his heirs, beneficiaries, legatees, executors, trustees and legal
guardians.

                  SECTION 2. Restriction on Transfer. No Stockholder shall
transfer any Voting Shares during the term of this Agreement unless, in each
case, either (i) the recipient of such Voting Shares shall agree in writing to
be bound by and comply with all applicable provisions of this Agreement as fully
as required of the transferor and be deemed to be a Stockholder hereunder, or
(ii) the transfer is pursuant to a registered public offering under the
Securities Act of 1933, as amended (the "Act") or pursuant to Rule 144 under the
Act.

                  SECTION 3. Legend on Stock Certificates. Each certificate
representing Voting Shares shall conspicuously bear the following legend until
such time as the shares represented thereby are no longer subject to the
provisions hereof:

                  "THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO THE
                  TERMS AND CONDITIONS OF AN AGREEMENT, DATED FEBRUARY 14, 2000,
                  AMONG THE COMPANY, HUGH J. O'KANE, JR., KEVIN M. O'KANE.
                  COPIES MAY BE OBTAINED AT NO COST BY WRITTEN REQUEST MADE BY
                  THE HOLDER OF RECORD OF THIS CERTIFICATE TO THE COMPANY."

                  The Company covenants that it shall file a copy of this
Agreement in its stock books and shall keep a copy thereof at its corporate
headquarters.

                  SECTION 4. Duration of Agreement. This Agreement shall
terminate upon the earlier to occur of either the (i) third anniversary of the
death of the first to die of Hugh O'Kane or Kevin O'Kane or (ii) the first date
upon which both individuals are deceased.

                  SECTION 5. Representations and Warranties. Each Stockholder,
severally and not jointly, represents and warrants to the Company and the other
Stockholders as follows:

                  (a) The execution, delivery and performance of this Agreement
by such Stockholder will not violate any provision of law, any order of any
court or other agency of government, or any provision of any indenture,
agreement or other instrument to which such Stockholder or any of its or his
properties or assets is bound, or conflict with, result in a breach of or
constitute (with due notice or lapse of time or both) a default under any such
indenture, agreement or other instrument, or result in the creation or
imposition of any lien, charge or encumbrance of any nature whatsoever upon any
of the properties or assets of such Stockholder.

                  (b) This Agreement has been duly executed and delivered by
such Stockholder
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and, when executed by the other parties hereto, constitutes the legal, valid and
binding obligation of such Stockholder, enforceable in accordance with its
terms, subject, as to enforcement of remedies, to applicable bankruptcy,
insolvency, fraudulent conveyance and similar laws and to limitations on the
availability of equitable remedies.

                  (c) The shares of Common Stock listed in Annex I opposite the
name of such Stockholder constitute all the shares of the capital stock of the
Company owned by such Stock holder on the date hereof.

                  SECTION 6. Headings. Headings of articles, sections and
paragraphs of this Agreement are inserted for convenience of reference only and
shall not affect the interpretation or be deemed to constitute a part hereof.

                  SECTION 7. Severability. In the event that any one or more of
the provisions contained in this Agreement or in any other instrument referred
to herein shall, for any reason, be held to be invalid, illegal or
unenforceable, such illegality, invalidity or unenforceability shall not affect
any other provisions of this Agreement.

                  SECTION 8. Benefits of Agreement. Nothing expressed by or
mentioned in this Agreement is intended or shall be construed to give any person
other than the parties hereto and their respective successors and permitted
assigns any legal or equitable right, remedy or claim under or in respect of
this Agreement or any provision herein contained, this Agreement and all
conditions and provisions hereof being intended to be and being for the sole and
exclusive benefit of the parties hereto and their respective successors and
permitted assigns.

                  SECTION 9. Notices. Any notice or other communications
required or permitted hereunder shall be deemed to be sufficient and received if
contained in a written instrument delivered in person or by courier or duly sent
by first class certified mail, postage prepaid, or by telecopy addressed to such
party at the address or telecopy number set forth below:

                  (1)      if to the Company, to it at:

                            Lexent Inc.
                            3 New York Plaza
                            New York, NY 10004
                            Attention: Chairman
                            Telecopy: (212) 981-2493


                           with a copy to:

                           Reboul, MacMurray, Hewitt,
                           Maynard & Kristol
                           45 Rockefeller Plaza
                           New York, NY 10111

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                           Attention: Joshua A. Leuchtenburg, Esq.
                           Telecopy: (212) 841-5725

                  (2) if to any Stockholder, to it at its address appearing on
Annex I hereto;

or, in any case, at such other address or telecopy number as shall have been
furnished in writing by such party to the other parties hereto. All such
notices, requests, consents and other communications shall be deemed to have
been received (a) in the case of personal or courier delivery, on the date of
such delivery, (b) in the case of mailing, on the fifth business day following
the date of such mailing and (c) in the case of telecopy, when received.

                  SECTION 10. Modification. Except as otherwise provided herein,
neither this Agreement nor any provision hereof may be modified, changed,
discharged or terminated except by an instrument in writing signed by the
parties hereto.

                  SECTION 11. Counterparts. This Agreement may be executed in
any number of counterparts, and each such counterpart hereof shall be deemed to
be an original instrument, but all such counterparts together shall constitute
but one agreement.

                  SECTION 12. GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY
THE LAWS OF THE STATE OF DELAWARE.
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                  IN WITNESS WHEREOF, each of the parties hereto has executed
this Agreement as a sealed instrument, all as of the day and year first above
written.

                               LEXENT INC.


                               By  /s/ HUGH O'KANE, JR.
                                  ----------------------------------
                                    Name: Hugh J. O'Kane, Jr.
                                    Title: Chairman

                                         /s/ HUGH O'KANE, JR.
                                  ----------------------------------
                                          Hugh J. O'Kane, Jr.

                                         /s/ KEVIN M. O'KANE
                                  ----------------------------------
                                           Kevin M. O'Kane

ACKNOWLEDGED AND CONSENTED TO
AS OF FEBRUARY 14, 2000


By /s/ PATRICIA O'KANE
   -------------------------------
   Name of Spouse: Patricia O'Kane

By /s/ MARGARET O'KANE
   -------------------------------
   Name of Spouse: Margaret O'Kane

HUGH J. O'KANE, JR. 2000 GRANTOR RETAINED ANNUITY TRUST

By /s/ KEVIN M. O'KANE
   --------------------------------
   Name of Trustee: Kevin M. O'Kane

By /s/ PATRICIA O'KANE
   --------------------------------
   Name of Trustee: Patricia O'Kane


HUGH J. O'KANE, JR. 2000 REMAINDER TRUST

By /s/ KEVIN M. O'KANE
   --------------------------------
   Name of Trustee: Kevin M. O'Kane

By /s/ PATRICIA O'KANE
   --------------------------------
   Name of Trustee: Patricia O'Kane