A highly efficient ring-opening addition reaction of benzoxazine at ambient temperature has been developed with 2-methylresorcinol as a nucleophilic reagent. In this reaction, 2-methylresorcinol reacted with two equivalent amount of benzoxazine to give the corresponding 1:2 adduct, demonstrating its potential as a bifunctional nucleophile. Based on this reaction, a new crosslinking system consisting of a polymer bearing benzoxazine moieties in the side chains and 2-methylresorcinol as a crosslinker has been performed to obtain the corresponding networked polymer. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012