Abstract The complexes [Ni(L 1)(PPh 3)] ( 1) and [Ni(L 2)(PPh 3)]·HCl ( 2) were synthesized by the reaction of [Ni(PPh 3)Cl 2] and dibasic 2-hydroxyacetophenone-S-R-4-R 1-thiosemicarbazones (R/R 1: H/CH 3, L 1H 2; CH 3/H, L 2H 2). The ligands and the complexes were characterized using elemental analysis, IR and 1H NMR spectra. In both complexes, the thiosemicarbazone ligands coordinate to nickel(II) by giving two protons. Complex 1 is formed through the phenolate oxygen, azomethine nitrogen and sulfur atoms of L 1 and the P atom of a triphenylphosphine ligand. In complex 2, L 2 is functional through an ONN donor set, containing a thioamide nitrogen instead of a sulfur atom. X-ray analysis indicated distorted square planar structures for the complexes, and the nickel atoms lie slightly above the planes structured by the donor atoms. In the crystal forms of 1 and 2, some phenyl ring protons of the phosphine ligand give intramolecular hydrogen bonds with the donor atoms of the thiosemicarbazone moiety, namely the phenolate oxygen (in complexes 1 and 2) and N 4 nitrogen (in complex 2).