10-[(4-Nitro-phen-yl)ethyn-yl]-10H-pheno-thia-zine.

The title compound, C20H12N2OS, is a 10-ethynyl-10H-pheno-thia-zine derivative. The pheno-thia-zine unit has a butterfly shape, where the folding angle between the two benzene rings is 153.87 (7)°, which is almost as in other reported pheno-thia-zine derivatives. The dihedral angle between the mean plane including the C atoms bonded to the pheno-thia-zine N atom and the benzene ring of the nitro-benzene group is 10.34 (5)°. The near planar geometry of the mol-ecule is reasonably explained by intra-molecular charge-transfer inter-actions.