A heterobifunctional monomer, namely, 3-(4-ethenylphenyl)-3,4-dihydro-2H-1,3-benzoxazine (VBOZN), which contains both vinyl group and benzoxazine group, was successfully prepared by three-step method with high purity and satisfactory yield. The chemical structure of VBOZN was identified by NMR, FTIR and elemental analysis. VBOZN selectively underwent free radical polymerization initiated by azodiisobutyronitrile to obtain homopolymer P(VBOZN) with M-n 4960 and M-w 11700. The benzoxazine-containing linear P(VBOZN) has T-g about 112 degrees C and shows better thermal stability than that of polystyrene. The P(VBOZN) was cured by heating without any catalyst and the peak temperature assigned to cationic ring-opening polymerization of P(VBOZN) centered at 244 degrees C. The molecular weight of P(VBOZN) could be improved dramatically by copolymerization of VBOZO with N-phenylmaleimide. Both homopolymer and copolymers show high stability and theoretical limiting oxygen index are near 30. P(VBOZN) and copolymers are not only new kinds of well-defined multifunction polymers with the potential of postpolymerization and/or chemical modification, they are also novel intrinsic fire retarded polymers. (C) 2015 Elsevier Ltd. All rights reserved.