Abstract: Calcium oxide was found efficient solid base catalyst for synthesis of chalcone under microwave condition. We employed this method for synthesis of various chalcone from various substituted ketone and aldehyde including o-hydroxy ketone and o-amino ketone. The merits of this methods are inexpensive and easily available solid base catalyst, shorter reaction time, high yield compared to other reported methods, avoid use of toxic regents and solvent free condition, applicable to base sensitive functional group.