In the title compound, C20H19NOS, the pyrrolizine ring is essentially planar (r.m.s. deviation = 0.001 Å) while the fused dihydro-pyrrolizine ring adopts an envelope comformation with the C atom bearing the methyl substituents as the flap. The dihedral angles between the pyrrolizine and the phenyl and thio-phene rings are 34.54 (7) and 44.93 (7)°, respectively. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into infinite zigzag chains parallel to the b-axis direction.