Abstract 2-(6-methyl-2-pyridyl)benzothiazole (mpbt) acts as a bidentate ligand coordinating through both nitrogen atoms. Cobalt(II) forms the tetrahedral complexes CoX 2mpbt (X = Cl, Br, I) and the polymeric five-coordinate complex Co(SCN) 2mpbt. Nickel(II) forms the tetragonal complexes NiX 2mpbt (X = Cl, Br, I) and the octahedral complex Ni(SCN) 2(mpbt) 2. The copper(II) complexes CuX 2mpbt (X = Cl, Br, SCN) are considered to be five- or six-coordinate in the solid state. The five-coordinate complexes [Cu(mpbt) 2ClO 4]ClO 4.nH 2O (n = 0,2) and [Cu(mpbt) 2Cl]ClO 4 were also isolated. The complexes Co(SCN) 2mpbt and Cu(SCN) 2mpbt are antiferromagnetic. The steric effect of the methyl group of mpbt on the spectra of the complexes is discussed.