The title compound (abbreviated as llPzAPH) has been synthesised and physico-chemically (IR, PMR, mass spectra) characterized for the first time. The coordinating behaviour of the thiosemi-carbazone has been investigated by isolation and characterization of its complexes with Co(ill), Ni(ll) and Gu(ll) having different counterions, Magnetic and spectral data indicate CoO’lPzAPjX (X = counter ion) as spin paired octahedral species with the ligand in the deprotonated thiol form, while Ni(MPzAPH) X and APH) Xareproposed to be spin-free octahedral with the ligand in the neutral thione form. A spin-paired diamagnetic Ni(MPzAP) (SCN) has also been identified. IR data point out that the pyrazolyl ring nitrogen (tertiary), the azomethine nitrogen and the sulphur atom are the points of attachment With the metal ion in all these complex species. © 1984, Taylor & Francis Group, LLC. All rights reserved.