Benzo[a][1,4]benzothia-zino[3,2-c]phenothia-zine.

The title compound, C(22)H(12)N(2)S(2), crystallizes in space group P2(1)/c with four mol-ecules in the asymmetric unit. The heterocyclic mol-ecule is quasi-planar with a dihedral angle between the phenyl rings on the periphery of the mol-ecule of 1.73†(19)°. Short H⋯S (2.92†à ) and C-H⋯π [2.836†(3)†à ] contacts are observed in the crystal with shorted π-π stacking distances of 3.438†(3)†à along the b axis. Surprisingly, and unlike a closely related material, this mol-ecule readily forms large crystals by sublimation and by slow evaporation from di-chloro-methane. The maximum absorbance in the UV-Vis spectrum is at 533†nm. Emission was measured upon excitation at 533†nm with a fluorescence λ(max) of 658†nm and cutoff of 900†nm.