Moreover, polybenzoxazines possess several outstanding properties such as near-zero shrinkage after curing, low water absorption, and relatively high Tg even though they render relatively low cross-linking density [6], [7] and [8]. To obtain high performance polybenzoxazines by utilizing its molecular design flexibility, thermal and thermo-oxidative stabilities of polybenzoxazines have been substantially improved by altering the functional group on the phenol and/or amine