We have developed a sequence-dependent synthesis of the amino-functionalized poly(ether sulfone) P2. The amino groups of P2 act as reactive sites toward epoxy resins. After curing P2 with diglycidyl ether of bisphenol A (DGEBA) and cresol novolac epoxy (CNE), we obtained the flexible, light-yellow, transparent, epoxy thermosetting films P2/DGEBA, and P2/CNE, respectively, having glass transition temperatures (Tg) of 258 and 274°C, respectively. In addition, we also prepared a flexible film after condensation of the amino groups of P2 with the anhydride groups of 4,4′-oxydiphthalic anhydride (ODPA); after imidization at 300°C for 1 h, the resulting P2/ODPA thermosetting film possessed a value of Tg of 340°C. These three thermosetting films also exhibited flame retardancy with a UL-94 VTM-0 grade. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40980.