Quaternary phosphine type hypercrosslinked polymer catalysts were successfully prepared using the Friedel–Crafts alkylation reactions, which benefit from the synergistic effects between the Brønsted acidity of the hydroxyl group and nucleophilicity of the Br⁻ group as well as the CO₂ capture of the ionic liquids. The as-obtained metal-free catalysts facilitate the cycloaddition and synthesis of high value-added fine chemicals.