The mol-ecule of the centrosymmetric title compound, C(18)H(20)N(2)O(6), assumes an E configuration with respect to the azomethine C=N bond. The imino group is coplanar with the aromatic ring. Intra-molecular O-H⋯O and O-H⋯N bonds are found between the hydroxyl groups and adjacent O (or N) atoms. In the crystal structure, inter-molecular O-H⋯O bonds link each mol-ecule to two others, forming a layered network.