The present invention provides an adenine modified solid, ordered, mesoporous, bifunctional, organo-inorganic silica-based catalyst, its method of preparation and also a process for the production of cyclic carbonates of the formula hereinbelow ##STR00001## wherein R.dbd.H, CH.sub.2Cl, CH.sub.3, C.sub.4H.sub.9, C.sub.6H.sub.11, C.sub.6H.sub.5.