Metal complexes with biologically important ligands have received a great attention in the last decades. The thiosemicarbazones and their complexes it is a permanent fiel of research due the numerous pharmacological properties and applications, with anticancer, bactericidal and fungicidal activity. The activity of the coordination compounds of transition metals is normally increased compared to the free thiosemicarbazones and depends largely on their structure and properties. So the crystallographic elucidation of these compounds is important and fundamental to evaluate their possible applications. We describe the synthesis of two new complexes, [Ni(L)Cl] (1) and [Pd(L)Cl] (2), with the ligand 2-acetylpyridine N4-phenylthiosemicarbazone (HL). The compounds have been characterized by elemental analysis and spectral (IR, UV-Vis, 1H NMR, and 13C NMR) measurements. Crystal and molecular structures of both complexes have been determined by single crystal X-ray analysis. It was found that the ligand coordinates with tridentate NNS donor atoms, in its deprotonatd tiona form. The chlorine ion is present in the coordination sphere for the both center atoms of the complexes, with Ni-Cl distance of 2.163(10) Å and Pd-Cl of 2.298(8) Å and displays the square-planar geometry with significantly distortion. The compounds are isoeletronic with d8 configuration and isostrutctural, also observed at spectroscopy analyses. Interestingly, the intermolecular hydrogen bonds have also been observed in both complexes and are responsible for the formation of a dimer-like structure in the crystal structure. For the purpose of complexation, all the techniques employed were compared with results obtained for the complex agent, and thus, to study with more clarity the influence of the metals in the structure, stability and property of these ligands. The biological potential applications of the compounds have been studied against cancer cells.