The title compound, C(16)H(14)F(3)N(3)OS·H(2)O, which had been previously characterized in the space group P-1 [Ren et al. (2011 ▶). Acta Cryst. E67, o270], has now been crystallized from 1-propanol in the monoclinic form in the space group P2(1)/c. While the triclinic form is a Z' = 2 crystal, the new monoclinic polymorph includes one main mol-ecule and one water lattice mol-ecule in the asymmetric unit. In the crystal, the water mol-ecule is sandwiched between neighboring main mol-ecules and behaves as both donor and acceptor in O-H⋯N and N-H⋯O hydrogen bonds with the imidazole N atoms. This pattern of chains parallel to [100] further inter-acts via O-H⋯N(pyridine) contacts.