Substituted coumarins are synthesized from phenols and ethyl acetoacetate or methyl acetoacetate via Pechmann condensation using heterogeneous recyclable catalyst (HClO4 (.) SiO2) under solvent-free conditions. This method is simple, cost effective, requires short reaction times and benefits from the elimination of production of acidic waste streams generated with conventional acid catalyst to give good yields. (c) 2006 Elsevier B.V. All rights reserved.