3,9-Dimethyl-2,3-dihydrospiro[carbazole-1,2 '-[1,3]dithiolan]-4(9H)-one

The title compound, C16H17NOS2, consists of a carbazole skeleton with methyl and dithiolane groups as substituents. In the indole ring system, the benzene and pyrrole rings are nearly coplanar, forming a dihedral angle of 1.02 (11)degrees. The cyclohexenone ring has a twisted conformation, while the dithiolane ring adopts an envelope conformation with one of the CH2 C atoms at the flap. In the crystal, weak C-H center dot center dot center dot O hydrogen bonds link the molecules into supramolecular chains nearly parallel to the c axis. These hydrogen bonds together with weak C-H center dot center dot center dot pi interactions link the molecules into a three-dimensional supramolecular network.