Commercially available LiOH.H2O was found to be a highly efficient dual activation catalyst for Claisen-Schmidt condensation of various aryl methyl ketones with aryl/heteroaryl aldehydes providing an easy synthesis of 1,3-diaryl-2-propenones under mild conditions. The reactions were carried out at room temperature and in short times affording high yields. Excellent chemoselectivity was observed with carbonyl substrates bearing halogen atom and nitro group without any competitive aromatic nucleophilic substitution. The resultant chalcones did not undergo Michael addition with the ketone enolate. The rate of Claisen-Schmidt condensation was found to be dependent on the steric and electronic factors of the carbonyl substrates. (c) 2005 Elsevier B.V. All rights reserved.