Crystal structure of 6-(p-tol­yl)benzo[b]naphtho[2,3-d]thio­phene and of an ortho­rhom­bic polymorph of 7-phenyl­anthra[2,3-b]benzo[d]thio­phene

The title compounds, C23H16S, (I), and C26H16S, (II), are benzo­thio­phene derivatives in which the benzo­thio­phene moiety is fused with a naphthalene ring system in (I), and with an anthracene ring system in (II). In (I), the mean plane of the benzo­thio­phene ring system makes a dihedral angle of 2.28 (6)° with the naphthalene ring system, and a dihedral angle of 1.28 (6)° with the anthracene ring system in (II), showing that the fused units are essentially planar. In (I), the 4-methyl­benzene ring substituent makes a dihedral angle of 71.40 (9)° with the naphthalene ring system, while the phenyl ring substituent in (II) makes a dihedral angle of 67.08 (12)° with the anthracene ring system. In the crystals of both compounds, mol­ecules are linked by C—H⋯π inter­actions, leading to the formation of slabs parallel to (001) in (I) and to zigzag chains along [001] in (II). There are also offset π–π inter­actions present within the slabs in (I). In the crystal of (II), they link the chains, forming sheets parallel to (010). The triclinic polymorph of compound (II) has been reported [Sivasakthikumaran et al., (2012[Sivasakthikumaran, R., Nandakumar, M. & Mohanakrishnan, A. K. (2012). J. Org. Chem. 77, 9053-9071.]). J. Org. Chem. 77, 9053–9071].