5-(1H-Tetra-zol-5-yl)-1H-indole monohydrate.

In the title compound, C(9)H(7)N(5)·H(2)O, the inter-planar angles between the benzene and tetra-zole rings and between the benzene and imidazole rings are 8.71 (3) and 1.32 (2)°, respectively. In the crystal, strong N-H⋯N hydrogen bonds link the organic 5-(1H-tetra-zol-5-yl)-1H-indole mol-ecules into chains extended along the b axis. The chains are further inter-connected into layers parallel to (100) via strong O-H⋯N and N-H⋯O hydrogen bonds. Furthermore, the layers are inter-connected via strong O-H⋯N hydrogen bonds. Moreover, cohesion between the layers is provided by the π-π inter-actions between the imidazole, tetra-zole and benzene rings with centroid-centroid distances of 3.766 (2), 3.832 (2) and 3.733 (2) Å.