2-Hydroxyethylammonium formate was used as cost-effective ionic liquid to develop a mild and environmentally friendly hetero-Michael reaction. The ionic liquid works both as reaction medium as well as catalyst and can be recycled efficiently without significant loss in activity. The reaction is applicable to various aromatic sulfur nucleophiles, secondary nitrogen nucleophiles and different activated olefins. (C) 2007 Elsevier B.V. All rights reserved.