The asymmetric unit of the title compound, [PtCl(C(32)H(24)N(5))](ClO(4))(2)·2CH(3)CN·1.5H(2)O, comprises two unique Pt(II) complex cations, four perchlorate anions, four acetonitrile solvent mol-ecules and three water mol-ecules. The Pt atom is four-coordinated by a tridentate chelating 2,2':6',2''-terpyridine ligand and a chloride ion in a square-planar geometry with modest distortion imposed by the constraint of the terpyridyl ligand. The r.m.s. deviations from the plane comprising the four ligand donor atoms and the Pt atom are 0.0381 and 0.0472 Å in the two complex cations.