Triazine-containing polytriphenylimidazolium network for heterogeneous catalysis of CO2 conversion to cyclic carbonates

•Triazine-containing poly(triphenylimidazole) (PTPIM) and poly(triphenylimidazolium) (PTPIM-IL) are synthesized.•PTPIM and PTPIM-IL show high specific surface areas of 982 m2/g and 570 m2/g, respectively.•PTPIM-IL exhibits excellent catalytic activity toward cycloaddition of CO2 to epoxides.•PTPIM-IL is very effective in converting cyclohexene oxide with high conversion (96%) and selectivity (99%).•High porosity, abundant imidazolium/triazine, and high nucleophilicity of I− play roles in the catalytic activity.