2,2′-Dihydroxy-3,3′-[(1E,1′E)-hydrazine-1,2-diylidenedimethylidyne]dibenzoic acid N,N-dimethylformamide disolvate

The title compound, C(16)H(12)N(2)O(6)·2C(3)H(7)NO, lies across a crystallographic inversion centre which is situated at the midpoint of the central N—N bond. The substitution at the C=N bond adopts a trans configuration and it is essentially coplanar with the benzene ring [N—C—C—C torsion angles = −173.9 (4) and 6.4 (6)°]. All torsion angles involving non-H atoms are close to 180°. Intra­molecular O—H⋯O and weak C—H⋯O hydrogen bonds form S(6) and S(5) ring motifs, respectively, while inter­molecular O—H⋯O and weak C—H⋯O hydrogen bonds connect the Schiff base mol­ecule to solvent dimethyl­formamide mol­ecules.