2-[((E)-2-{2-[(E)-2-Hy-droxy-benzyl-idene]hydrazinecarbon-yl}hydrazinyl-idene)meth-yl]phenol.

The mol-ecule of the title compound, C(15)H(14)N(4)O(3), is completed by the application of crystallographic twofold symmetry, with the carbonyl group lying on the rotation axis. The mol-ecule is close to planar: the greatest deviation of a torsion angle from 0° is 7.3 (2)° about the bond linking the phenol ring to the rest of the mol-ecule. An intra-molecular O-H⋯N(imine) hydrogen bond is formed in each half of the mol-ecule. The carbonyl O atom is anti with respect to the amine H atoms and this allows for the formation of N-H⋯O(hydrox-yl) hydrogen bonds in the crystal, which results in supra-molecular layers lying parallel to (100).