Abstract: | The molecule of the former title compound, C13H9ClN2O2, (I), is nearly planar, with an intramolecular O⋯O hydrogen bond of 2.692 (2) Å. The latter title compound, C17H18ClN3O4, (II), exists in the keto–amine tautomeric form, with a strong intramolecular hydrogen bond of 2.640 (2) Å between the O and N atoms, the H atom being bonded to the N atom. The azobenzene moieties of both molecules have trans configurations, and the dihedral angle between the planes of the two aromatic rings is 4.1 (1)° in (I) and 9.9 (1)° in (II). The N—H⋯O hydrogen‐bonded rings are almost planar and coupled with the cyclohexadiene rings in (II). |