3,9-Dimethyl-2,3-dihydro-spiro-[carb-az-ole-1,2'-[1,3]dithio-lan]-4(9H)-one.

The title compound, C16H17NOS2, consists of a carbazole skeleton with methyl and dithiol-ane groups as substituents. In the indole ring system, the benzene and pyrrole rings are nearly coplanar, forming a dihedral angle of 1.02 (11)°. The cyclo-hexenone ring has a twisted conformation, while the dithiol-ane ring adopts an envelope conformation with one of the CH2 C atoms at the flap. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into supra-molecular chains nearly parallel to the c axis. These hydrogen bonds together with weak C-H⋯π inter-actions link the molecules into a three-dimensional supramolecular network.