Novel polybenzoxazine precursor containing m-carborane unit in the main-chain has been firstly synthesized through click reaction of diazidomethyl m-carborane (DAMC) and diacetylene bisbenzoxazine (DABB). Meanwhlie, the traditional polybenzoxazine precursor was also prepared through click reaction of diazidomethyl p-benzene (DAPB) and DABB as a control. 1H NMR was used to confirm the structures of the monomers and the resulting polymers. FT-IR and differential scanning calorimetry (DSC) were used to study the curing behavior of carborane-containing benzoxazine polymer (CCBP). Dynamic mechanical analysis (DMA) study demonstrated that the cured CCBP had high storage moduli and high Tg. Thermogravimetric analysis (TGA) and ablation test showed that the cured CCBP had outstanding thermo-oxidative stability. During thermal ablation of cured CCBP, organic material was degraded, and a passivation layer with oxidized m-carboranes was formed, which prevented the underlying polymer from further degradation. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 973-980