A novel 2-oxazoline-benzoxazine (POB) was synthesized with 2-(hydroxylphenvl)-2-oxazoline, 1,3,5-triphenylhexahydro-1,3,5-triazine and paraformaldehyde. The chemical structure of the monomer was confirmed by FTIR, H-1-NMR, C-13-NMR, and MS. The curing behavior of the monomer was studied by DSC and FTIR, and the ring opening reaction of the monomer was found to occur from 187.5 degrees C. The results of DMA and TGA demonstrated that the thermal properties of polymer for POB monomer (P-m) are better than polymer for POB precursor (P-p), because that the oligomer in benzoxazine precursor decreased the perfection of the polymer's network structure; it was also found that the thermal properties of P-m and P-p are much better than the common polybenzoxazine and the composite material of benzoxazine and 2-oxazoline. (C) 2008 Wiley Periodicals, Inc.