There is a remarkable stereochemical difference between the free ligand and that coordinated to the Ni atom in the title compound {systematic name: bis[1-(2-naphthyliminomethyl)-2-naphtholato-N,O]nickel(II), [Ni(C21H14NO)(2)]}. Upon coordination, the orientation of the N-(beta-naphthyl)-2-oxy-1-naphthaldimine ligand (which is almost planar in the solid state when uncomplexed) is changed so that the plane of the N-beta-naphthyl substituent is almost normal to the plane of the naphthaldiminato moiety. Two bidentate ligands coordinate to the Ni atom (which lies on an inversion centre) with their O and N atoms in a (necessarily) trans arrangement and forming a stepped conformation with a mean chelate-plane vertical separation of 0.639 (2) Angstrom. Main dimensions are Ni-O 1.820 (2), Ni-N 1.901 (2) Angstrom and O-Ni-N 91.75 (7)degrees.