Highly cross-linked porous poly(N-vinylimidazole-co-divinylbenzene) (PVIm) beads of various pore sizes and specific surface areas were synthesized by suspension polymerization. The surfaces of the PVIm beads were then modified with various alkyl halides to obtain various ionic liquid-grafted porous polymer beads (PVIm-RX), which were then used as heterogeneous catalysts in the synthesis of cyclic carbonate from CO2 and epoxide. All catalytic reactions are carried out under mild conditions (90-130 degrees C, 0.86-2.17 MPa) in the absence of organic solvents. The effects of texture properties of the PVIm matrix, molecular compositions of the ionic liquid moieties, and catalytic reaction parameters (reaction temperature, pressure, and time) on the catalytic reactivity of cycloaddition reactions were systematically investigated. The results demonstrate that grafted ionic liquids with more nucleophilic anions, bulkier alkyl chains, or hydroxyl groups improve reactivity. Additionally, the,incorporation of small amount of ethanol or water into the reaction system could significantly increase reactivity. In addition, textural properties of the polymer matrix (pore size and specific surface area) affected the catalytic reactions. The obtained PVIm-RX heterogeneous catalysts exhibited higher turnover number than those reported for ionic liquids grafted onto porous silica. (C) 2011 Elsevier B.V. All rights reserved.