4-Dimethylamino 2-aza-1,3-diene 2a,b derived respectively from methyl N-(1- ethoxyethyliden)glycinate 1a and methyl N-[bis-(methylthio)methylene]glycinate 1b react with hydrazines 3a,b and amines 3c,d to give the corresponding new imidazole-4-carboxylates 5(a-f) by a solvent-free aza-annulation. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.