Condensation of thiosemicarbazones 2 derived from 1-tetralones ( 1) with chloroacetic acid in presence of N-methylpyridinium tosylate (an ionic liquid) yields 2-substituted-4-thiazolidinones 3. The reaction of 2 with α-halo carbonyl compounds at room temperature under grinding conditions yields 2,4-disubstituted thiazoles 4 in excellent yields. The structures of compounds 2-4 have been established on the basis of elemental analysis, IR, NMR and mass spectral data.