With certain cationic initiators benzoxazine rings can be opened and polymerized at room temperature. Fourier transform infrared spectroscopy,H-1 and C-13 nuclear magnetic resonance spectroscopy, size exclusion chromatography, differential scanning calorimetry, and thermogravimetric analysis have been used to monitor the polymerization process and to characterize the obtained polymers. High performance bisphenol-A/aniline based polybenzoxazine with glass transition (T-g) at 220 degrees C and char yield of approximately 60% at 800 degrees C under nitrogen is obtained.