The ligand (HL) was synthetized by the reaction of 2-acetylthiazole and thiosemicarbazide in molar ratio 1:1 in water. In the reaction of ligand (HL) and nickel(II) tetrafluoroborate hexahydrate [Ni(HL)2](BF4)2 complex was obtained. The Ni(II) ion has octahedral coordination geometry. The tridentate ligand (HL) is coordinated to the nickel ion with a NNS set of donor atoms forming two five- -membered chelate rings. The ligand (HL) and the [Ni(HL)2](BF4)2 complex were characterized by elemental analysis, IR and UV/Vis spectroscopy and the structure of the complex was defined by X-ray analysis.