A simple highly versatile and efficient synthesis of 2,45-trisubstituted imidazoles is achieved by three component cyclocondensation of 1,2-dicarbonyl compounds, aldehydes and NH4OAc, as ammonia source using clays, zeolite, nano-crystalline sulfated zirconia (SZ) as catalyst in ethanol at moderate temperature. Moreover, the utility of this protocol was further explored conveniently for the one-pot, four component synthesis of 1,2,4,5-tetrasubstituted imidazoles in high yields, short reaction times and milder conditions, easy work-up and purification of products by non-chromatographic methods. The catalysts can be recovered for the subsequent reactions and reused without any appreciable loss of their efficiency. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.