Novel side-chain benzoxazine functional polyvinylchloride (PVC-Benzoxazine) was synthesized by using "Click Chemistry" strategy. First, approximately 10% of chloro groups of PVC were converted to azido groups by using NaN3 in N,N-dimethylformamide. Propargyl benzoxazine was prepared independently by a ring closure reaction between p-propargyloxy aniline, paraformaldehyde, and phenol. Finally, azidofunctionalized PVC was coupled to propargyl benzoxazine with high efficiency by click chemistry. The spectral and thermal analysis confirmed the presence of benzoxazine functionality in the resulting polymer. It is shown that PVC containing benzoxazine undergoes thermally activated curing in the absence of any catalyst forming PVC thermoset with high thermal stability. (C) 2008 Wiley Periodicals, Inc.