In the title compound, C19H23N3OS, the oxa-diazole and benzene rings are inclined at a dihedral angle of 50.30 (11)°, with the major twist between them occurring at the ring-methyl-ene N-C bond [N-N-C-N torsion angle = -101.2 (2)°]. In the crystal, helical supra-molecular chains along [010] are sustained by N-H⋯S hydrogen bonds. These are linked into layers lying parallel to (-101) by methyl-ene-phenyl C-H⋯π inter-actions.