4-{[(1,3-Benzothia-zolium-2-yl)hydra-zono](phen-yl)meth-yl}-3-methyl-1-phenyl-1H-pyrazol-5-olate monohydrate

The title compound, C(24)H(19)N(5)OS·H(2)O, was synthesized by the reaction of 4-benzoyl-3-methyl-1-phenyl-pyrazol-5-one and 2-hydrazino-1,3-benzothia-zole. Proton transfer leads to the formation of a zwitterionic structure and the mol-ecule exists in the enolate form. The pyrazolone ring makes dihedral angles of 35.4 (3), 69.7 (3) and 40.1 (3)° with the 1-phenyl, indirectly bound phenyl and benzothia-zole ring systems, respectively. The mol-ecules are linked into one-dimensional chains by a combination of N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds.