In conclusion, our experimental investigation of the reaction of CO2 with epoxides to give the corresponding cyclic carbonate showed that mixed metal oxides can be efficient catalysts in the overall process. We demonstrated that MgCrO and NiAlO were the most active MMOs and that the presence of KI or TBAI as catalysts and ethanol as the solvent were decisive for achieving high yields of cycloaddition under atmospheric pressure at 70 °C.