An efficient and practical synthesis of 5-[1-substituted-5-(4-substitutedphenyl)-4,5-dihydro-1H-pyrazol-3-yl]-4- methyl-1-phenyl-1H-imidazole-2-thiols was achieved through cyclisation of α, β-unsaturated ketones (chalcones) with hydrazine hydrate, phenyl hydrazine, 2, 4-dinitrophenyl hydrazine, isoniazide in catalytic amount of sulphuric acid under thermal condition in ethanol gives (3a-c), (4a-c), (5a-c), (6a-c) respectively and (7a-c) has been synthesized by the treatment of (3a-c) with benzoyl chloride in pyridine. All the synthesized compounds were characterized on the basis of melting point, IR spectra, NMR spectra and MASS spectra.