AbstractA highly efficient and enantioselective organocatalyst, imidazolidin‐4‐one, has been successfully immobilized on siliceous MCF and polymer‐coated MCF. The resulting heterogenized catalyst demonstrated excellent catalytic performance and recyclability for Friedel–Crafts alkylation and Diels–Alder cycloaddition. The performance of the supported catalysts in relation to the surface environment of siliceous MCF was examined. It was found that partially pre‐capping the MCF with TMS groups enabled us to attain well‐dispersed catalysts on the siliceous support with optimal performance. We have also developed a polymer‐coated MCF, which retained the porous structure of MCF without the surface silanol groups. High reactivity and excellent recyclability were achieved by the organocatalyst immobilized on polymer‐coated MCF.