In the imidazo[2,1-b][1,3] thiazole group of the title compound, C21H17ClN4O2S, the dihedral angle between the thiazole and imidazole rings is 1.9 (2)degrees. The mean plane of this group makes dihedral angles of 5.5 (2) and 39.9 (2)degrees with the benzene rings of the chlorophenyl and methoxyphenyl groups, respectively. The dihedral angle between these two benzene rings is 34.4 (2)degrees. In the crystal, molecules are connected to each other by intermolecular N-H center dot center dot center dot O hydrogen bonds along the b axis, generating a C(4) chain. Weak C-H center dot center dot center dot pi interactions also occur.