Abstract: Cadmium (C20H16Cd2N4O4Se4) (I) and nickel (C10H8N2NiO2Se2) (II) selenolates are synthesized by the exchange reactions of sodium 1-oxypyridyl-2-selenolate and cadmium(II) and nickel(II) chlorides. The molecular and crystal structures of the complexes are determined by X-ray structure analysis (CIF files CCDC nos. 1585246 (I) and 1585251 (II)). Complex I forms a centrosymmetric dimer in which the coordination polyhedron of the cadmium atom is a distorted trigonal bipyramid and the selenium atoms take the trans configuration. Complex II containing the solvate C2H5OH molecule has a square structure and is a monomer. Unlike complex I, in complex II the selenium atoms of the ligands take the cis configuration. The crystal packings in complexes I and II are formed by weak intermolecular hydrogen bonds C–H···O and C–H···Se. © 2019, Pleiades Publishing, Ltd.