(E,E)-4-{4-[3-(4-Chloro­anilino)-1-hydroxy­but-2-enyl­idene]-3-methyl-5-oxo-4,5-dihydro-1H-pyrazol-1-yl}­benzene­sulfonamide

The mol­ecule of the title compound, C(20)H(19)ClN(4)O(4)S, features a central pyrazole ring that possesses a benzene substituent, as well as a conjugated =C—C=C—C(meth­yl) substituent. The benzene ring is slightly twisted [dihedral angle = 7.7 (2)°] with respect to the five-membered ring; the mean plane of the zigzag =C—C=C—C fragment [torsion angle = 178.0 (4)°] is also slightly twisted [dihedral angle = 10.6 (4)°]. The amine and hy­droxy groups form intra­molecular hydrogen bonds. The amide group uses one of its H atoms to form a hydrogen bond to the sulfamyl O atom of an inversion-related mol­ecule. Adjacent dimers are further linked by an N—H(amido)⋯N(pyrazole) hydrogen bond to generate a linear chain. The crystal studied is a nonmerohedral twin with a minor twin component of 25.6 (2)%.