catena-Poly[[zinc-bis-(μ-2-sulfido-1H-benzimidazol-3-ium-5-carboxyl-ato)-κO:S;κS:O] trihydrate].

In the title compound, {[Zn(C(8)H(5)N(2)O(2)S)(2)]·3H(2)O}(n), the Zn(II) atom, lying on a twofold rotation axis, is four-coordinated by two S atoms and two O atoms from four 2-sulfido-1H-benzimidazol-3-ium-5-carboxyl-ate (H(2)mbidc) ligands in a distorted tetra-hedral geometry. Two H(2)mbidc ligands bridge two Zn(II) atoms, generating a double-chain along [[Formula: see text]01]. Adjacent chains are linked by N-H⋯O and O-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular network. One of the two water molecules also lies on a twofold rotation axis.