Sluggish and narrow process window of phthalonitrile resin has tremendously limited their wide applications. In this work, a novel phthalonitrile containing benzoxazine (4,4'-(((propane-2,2-diylbis (2H-benzo [e] [1,3]oxazine-6,3 (4H)-diyl) bis(3,1-phenylene))bis(oxy)) diphthalonitrile, BA-ph) with ortho-diallyl bisphenol A (DABPA) was investigated. The processing window of the BA-ph/DABPA blends were found from 50 degrees C to 185 degrees C, which was significantly broader than that of the pure BA-ph (120-200 degrees C). The composites were prepared through a curing process involving sequential polymerization of allyl moieties, ring-opening polymerization of oxazine rings and ring-forming polymerization of nitrile groups. BA-ph/DABPA/GF(glass fiber) composite laminates were prepared in this study, and the composite laminate with BA-ph/DABPA molar ratio of 2/2 showed an outstanding flexural strength and modulus of 560 MPa and 37 GPa, respectively, as well as a superior thermal and thermo-oxidative stability up to 408 and 410 degrees C. These outstanding properties suggest that the BA-ph/DABPA/GF composites are suitable candidates as matrices for high performance composites. (C) 2015 Society of Plastics Engineers