The reaction of resorcinol with ethyl acetoacetate (Pechmann reaction) or with acrylic acid over novel Nafion resin/silica composite materials with 40 and 80 wt% of Nafion in silica produces 7-hydroxycoumarins in high yields, under mild reaction conditions in short reaction time. Other solid acid catalysts were tested for comparison reasons. (C) 2003 Elsevier Inc. All rights reserved.