Complexes of oxalic acid dihydrazide (ODH, L1) with Co2+, Ni2+, Zn2+, and Pd2+ salts were isolated and characterized by elemental analyses, spectral (IR, Uv-Vis., mass), TGA, and magnetic measurements. The complexes are of the types, [Ni2(ODH-H)(OH)2(CH3OH)2H2O].H2O, [Ni(ODH-H)(H2O)2Cl], [Co2(ODH-2H)Cl2H2O)6 CH3OH].3H2O, [Zn3(ODH-H)2(OCH3)2(CH3OH)2].H2O, [Co(ODH-H)2(H2O)2], and [Pd3(ODH-H)2Cl4](H2O)2].2CH3OH. In the first three complexes, the ligand behaves in a bidentate manner; and is coordinated through NH and the enolized carbonyl oxygen groups with a removal of a proton from the latter group. Also, it acts as a bidentate ligand coordinated through the enolized (C=O) and (C=N) groups with the removal of a proton from the former group forming a five-membered ring around the Co2+ ion in the complex, [Co(ODH-H)2(H2O)2]. Finally, two ligands bonded three Pd2+ ions in which the terminal two palladium ions are bonded through the (C=O) and the (C=N) moieties forming two five-membered rings around the Pd2+ ions, while the intermediate Pd2+ ion is coordinated to two NH and two enolized carbonyl oxygen with the removal of two protons forming two five-membered rings around the Pd2+ ion. The geometries of the complexes were determined depending on the spectral and magnetic measurements.