Diquino[4,3- b ;3',4'- e ][1,4]thiaseleninePart XCVI in the series of Azinyl Sulfides.

The title compound, C18H10N2SSe, is a pentacyclic ring system folded along the S center dot center dot center dot Se vector. The central thiaselenine ring adopts a boat conformation and the two halves of the molecule are related by a crystallographic mirror plane.