Pyridinium-based ionic porous organic polymers (Py-iPOPs) were constructed from newly designed acetonitrile-functionalized ionic liquids and multi-carbaldehyde monomers by base-catalyzed Knoevenagel condensation. The obtained Py-iPOPs having in situ formed hydroxide anions and pyridinyl radicals were regarded as efficient metal-free and halogen-free heterogeneous catalysts for atmospheric CO2 fixation under mild conditions.
