Salicylaldehyde hydrazones derived from acyldicarboxylic acids (H4Ln, where n = 0, 1, 2, 4, 6, 8, 10, 14 and is the number of methylene units) of varying chain length have been prepared, and their dicopper(II) complexes have been isolated as bis analogues of antitumor carboxylate hydrazones. The predominant structural form adopted is polymeric, with [{Cu2Ln}(m)] formed in neutral or basic solution, [{Cu-2(H2Ln)Cl-2}(m)] from dilute HCl, and [{Cu-2-(H2Ln)}(m)].(ClO4)(2m) from dilute HClO4. The crystal structures of [Cu-2(H2L1)(H2O)(2)].(ClO4)(2) . 3H(2)O and [{Cu-2(H2L4)(C2H5OH)(2)}(m)].(ClO4)(2m). m(C2H5OH) have been determined. The structure of [Cu-2(H2L1)(H2O)(2)].(ClO4)(2) . 3H(2)O consists of discrete di-Cu(II) molecules with nonsymmetry-related Cu(II) centers. The copper atoms are square-planar with H2L1 supplying two tridentate, monoanionic ONO domains and water completing the coordination sphere. The two metal-binding domains are inclined at 80 degrees to each other. For [{Cu-2(H2L4)(C2H5OH)(2)}(m)].(ClO4)(2m). m(C2H5OH) the symmetry-related copper atoms are square-pyramidal with the base composed of H2L4, acting as a tridentate ONO chelator, and an O-bonded ethanol molecule. Axial phenolate bridges complete the coordination sphere, linking molecules to give a polymer. Compounds prepared have been characterized by a range of physicochemical and spectroscopic techniques, and proton and metal ion stability constant data have been determined.