In the two independent molecules in the asymmetric unit of the title compound, C13H9N3O2S, the azatricyclotridecapentaene ring system is approximately planar with r.m.s. deviations of 0.022 and 0.033 Å. The urea unit connected to the fused rings is approximately perpendicular [dihedral angles = 82.4 (1) and 82.7 (1)°]. In the crystal, the molecules associate by N—H⋯O hydrogen bonds, forming a chain running along the a axis. The crystal studied was a non-merohedral twin with a fractional contribution of 49.6 (1)% for the minor domain
