The oxidative methylation of acetone, acetophenone and diphenylmethane with methane has been investigated over sodium, cesium and sodium-cesium promoted magnesia catalysts at 750-degrees-C and under normal atmospheric pressure. All these compounds do react with methane and produce their corresponding methane coupling products. The bialkali (5 mol-% Na-5 mol-% Cs) promoted MgO catalyst provided higher product yields than the individual mono-alkali promoted MgO catalyst at the same alkali content of 10 mol-%.