In the title compound, C(16)H(14)ClNO(3)S, the dihedral angle between the almost-planar benzothia-zole ring system [maximum deviation = 0.012 (3) Å] and the aromatic ring of the trimeth-oxy-phenyl group is 15.56 (6)°. In the crystal, the mol-ecules are arranged into layers parallel to the bc plane, held together only by weak van der Waals forces.