Two kinds of supported homogeneous catalysts have been used in the synthesis of dimethylcarbonate from methanol and carbon dioxide. Bu2nSn(OMe)2 and [Nb(OMe) 5 ] 2 , that are reported to be active catalysts under homogeneous conditions, have been bound to a solid support. The moiety [–Bu n Sn(OMe) 2 ] has been grafted on a polystyrene resin by using a phenylethylene spacer, while the [Nb(OMe) 5 ] 2 moiety and NbOCl 3 have been linked to a silesquioxane matrix. The grafted tin metallorganic species is still active in the synthesis of DMC from methanol and CO 2 : tin is not lost during catalysis and the heterogenized catalyst can be easily recovered and reused. Conversely, the Nb-silesquioxane adduct is either a monomer or a dimer that does not bring any –OMe moiety linked to Nb and does not react with CO 2 nor with methanol, resulting to be inactive in catalysis.