Multiple catalytic polymerization of phthalonitrile resin bearing benzoxazine moiety: Greatly reduced curing temperature

•Dicyandiamide was used as catalyst to promote the polymerization of benzoxazine-containing phthalonitrile resin.•Dicyandiamide could catalyze both the ROP of benzoxazine and polymerization of nitrile groups and greatly lower the curing temperature.•Polymer films can be obtained after curing at 200 °C from the benzoxazine-functionalized phthalonitrile resin.•The phthalonitrile resins catalyzed by dicyandiamide show high thermal stability.