The three-component synthesis of 2,4,5-trisubstituted imidazoles, a typical acid-catalyzed reaction, could be conducted successfully with good to excellent yields in a neutral ionic liquid, 1-methyl-3-heptyl-imidazolium tetrafluoroborate ([HeMIM]BF4), under solvent-free and microwaveassisted conditions. The combined merits of microwave irradiation and ionic liquid make the three-component condensation with safe operation, low pollution, rapid access to products and simple workup. (c) 2006 Elsevier B.V. All rights reserved.