In the title mol-ecule, C17H15ClN4S, the benzene rings form dihedral angles of 16.6 (1) and 77.2 (1)° with the triazole ring. The dihedral angle between the benzene rings is 86.6 (1)°. In the crystal, pairs of N-H⋯S hydrogen bonds form inversion dimers with graph-set notation R 2 (2)(8). Weak C-H⋯S hydrogen bonds link these dimers into layers parallel to (100). Weak intra-molecular C-H⋯S and C-H⋯N contacts are observed.