Four different double metal cyanides (NiHCFe, CrHCFe, MnHCFe and ZnHCFe) were synthesized, followed by adsorbed on silica gel and used as Lewis acid catalyst in the isomerisation of substituted 2'-hydroxychalcones to flavanones under solvent-free (dry) condition. Optimization of the reaction condition, temperature effects, DMC catalysts loading and re-useable catalytic activity were further studied during the reaction. Among these catalysts, NiHCFe at 35 mol% loading gave excellent yield (90%) at 100 degrees C temperature in 1.15 h. Catalyst (NiHCFe) easily recovered and re-used six times without much loss of its catalytic activity which gave 80-85% product yields each time. However, these DMCs were failed to give product in the solution phase even prolonging the reaction time at reflux temperature. Similarly, isomerization of substituted 2'-aminochalcones gave 2-5% yields either in solution phase or under solvent-free condition. (C) 2013 Elsevier B.V. All rights reserved.