The asymmetric unit of the title compound, tetra-aqua-tetrakis-{μ(3)-6,6'-di-oxido-2,2'-[1,2-phenyl-enebis(nitrilo-methyl-idyne)]diphenolato}octa-zinc(II) dimethyl sulfoxide tetra-solvate dihydrate, [Zn(8)(C(20)H(12)N(2)O(4))(4)(H(2)O)(4)]·4C(2)H(6)OS·2H(2)O, contains one quarter of a Zn(II) octa-nuclear complex with symmetry, one dimethyl sulfoxide mol-ecule and one half of a water mol-ecule which lies on a twofold rotation axis. The Zn(II) atoms of the octa-nuclear complex have two different five-coordinate environments, viz. ZnN(2)O(3) and ZnO(5). All eight Zn(II) centers adopt a distorted square-pyramidal coordination; four Zn(II) ions have the N(2)O(2) tetra-dentate Schiff base ligand bound in a basal plane and the coordinated water mol-ecule occupying the apical site, while the remaing four Zn(II) ions are bound by five O atoms from three Schiff base ligands. In the crystal structure, Zn(II) complex mol-ecules, coordinated and uncoord-inated water mol-ecules and dimethyl sulfoxide mol-ecules are linked via O-H⋯O and C-H⋯O hydrogen bonds and C-H⋯π inter-actions, forming a three-dimensional framework.