In the title compound, C(19)H(14)OS, the naphtho-thio-phene moiety is almost planar except for the S atom of the five-membered ring, which is situated 0.047 (6) Å out of the C(4) plane (with an r.m.s. deviation of fitted atoms = 0.0009 Å). The dihedral angle between the naphtho-thio-phene plane and the attached meth-oxy-phenyl ring is 67.6 (2)°. In the crystal, a C-H⋯π inter-action is observed between a meth-oxy-phenyl C-H group and the outer benzene ring of the naphtho-thio-phene moiety. The five-membered ring of the naphtho-thio-phene moiety is disordered, with the S and opposite non-fused C atom approximately exchanging positions, with a site-occupancy factors of 0.808 (3) and 0.187 (3).