Theasymmetric unit of the title salt, C19H17N2S(+)·Cl(-)·0.75H2O, contains two symmetrically independent formula units of the carbenium salt along with three water mol-ecules. The water mol-ecules are only 50% occupated, and one of them is positioned in a hydro-phobic pocket not forming any hydrogen bonds. The conformation of the independent cations is very similar, with dihedral angles of 61.0 (2) and 61.5 (3)° between the benzene rings. They form quasi-centrosymmetric couples via π-π stacking inter-actions between the benzene and imidazo[2,1-b]thia-zole rings [centroid-centroid distances = 3.718 (3) and 3.663 (3) Å]. In the crystal, O-H⋯Cl hydrogen bonds lead to the formation of a helical anion-water chain along the c-axis direction. The cations connect to the anion-water chain through C-H⋯Cl inter-actions, generating a three-dimensional supra-molecular network. O-H⋯S hydrogen bonds and C-H⋯O inter-actions also occur.