The synthesis of chalcones via Claisen-Schmidt condensation between benzaldehyde and acetophenone by sonochemical and thermally-activated reactions over a new type of zeolite as catalyst is reported. The catalysts were prepared by grafting amino groups on sodium and cesium exchanged X zeolite. In this green, solvent free procedure, chalcones are selectively produced in very high yields (> 95%) when cesium exchanged X-NH2 is employed under ultrasound activation (c) 2006 Elsevier B.V. All rights reserved.