Some differently substituted 3-aryl-4, 5-dihydropyrazoles-1-carbothioamides have been synthesised with the aim to investigate their monoamine oxidase inhibitory activity. The chemical structures of the compounds have been characterized by means of their IR, 1H NMR, 13C NMR spectroscopic data and elemental analyses. All the active compounds showed a selective activity towards the B isoform of the enzyme, regardless of the ...