4-[(3-chlorophenyl)diazenyl]-2-([tris(hydroxymethyl)methyl]aminomethylene)cyclohexa-3,5-dien-1(2H)-one.

The title compound, C(17)H(18)ClN(3)O(4), adopts the keto-amine tautomeric form and displays an intramolecular N-H...O hydrogen bond [N...O = 2.639 (2) A]. The configuration around the azo N=N double bond is trans, and the dihedral angle between the planes of the two aromatic rings is 20.5 (2) degrees. The molecules are linked by O-H...O hydrogen bonds to form a three-dimensional network.