A novel aromatic ether nitrile monomer containing propenyl groups, 2,6-di{2-[(E)-1-propenyl]phenoxyl} benzonitrile (DPPB), was synthesized by the reaction of 2,6-dichlorobenzonitrile and 2-allylphenol using anhydrous potassium carbonate as the acid acceptor, N-methyl pyrrolidone as the dipolar aprotic solvent, and toluene as the dehydrating agent. The chemical structure of DPPB was characterized by FTIR and H-1-NMR. The monomer was used to modify a popular commercial bismaleimide, 4,4-bismaleimidodiphenylmethane (BMDPM), to improve the shear strength of the resin. The results showed that DPPB could effectively improve the shear strength of the BMDPM resin without decreasing the heat resistance of BMDPM. A better result was obtained when the composition of DPPB in the copolymer was 45 wt %.