Exhibit 1.1 VAN KAMPEN UNIT TRUSTS, SERIES 1263 TRUST AGREEMENT Dated: October 2, 2012 This Trust Agreement among Van Kampen Funds Inc., as Depositor, The Bank of New York Mellon, as Trustee, Cohen & Steers Capital Management, Inc., as Supervisor,...Trust Agreement • October 2nd, 2012 • Van Kampen Unit Trusts Series 1263
