Experimental

R factor = 0.072; wR factor = 0.156; data-to-parameter ratio = 28.3. The whole molecule of the title compound, C26H16N2S4, is generated by twofold rotational symmetry. The carbazole skeleton is nearly planar [maximum deviation = 0.054 (5) Å]. In the crystal, aromatic – stacking is observed between parallel carbazole ring systems of adjacent molecules, the shortest centroid–centroid distances between pyrrole and benzene rings being 3.948 (3) and 3.751 (3) Å. Related literature For tetrahydrocarbazole systems present in the framework of a number of indole-type alkaloids of biological interest, see: Saxton (1983). For related structures, see: Hökelek et al. (1994, 1998, 1999); Patır et al. (1997); Hökelek & Patır (1999). For hole-transporting mobility of charge carriers, see: Cloutet et al. (1999). For photoluminescence efficiencies, see: Zhenhong et al. (2006). For electroluminescent applications, see: Tirapattur et al. (2003). For photoactive devices, see: Taoudi et al. (2001). For sensors and rechargable batteries, see: Saraswathi et al. (1999). For electrochromic displays, see: Sarac et al. (2000)