A series of diamine-based benzoxazine precursors have been prepared using 4,4'-diaminodiphenyl methane, formaldehyde, and different phenol derivatives including phenol, p-cresol, and 2-naplithol. Their chemical structures were identified by FTIR, H-1 NMR, and elemental analysis. The curing reactions of those precursors were monitored by FTIR and DSC. The obtained materials exhibited higher glass transition temperature and char yields than the corresponding bisphenol-A based polybenzoxazines. The polybenzoxazine prepared from phenol showed the highest char yields of 65"% and thermal stability with 5 and 10% weight-loss temperatures at 346 and 432 degrees C, respectively. The polybenzoxazine prepared from 2-naphthol exhibited the highest glass transition temperature at 244 degrees C. (c) 2007 Wiley Periodicals, Inc.