The binding properties of ethylene-N,N＇-dianthranilate （EDA） and Ni（II） were studied by difference UV-Vis in 0.05 M Tris-HCl buffer （pH 7.4）. The stoichiometric ratio of EDA to nickel （1：1） was confirmed and the conditional binding constant （IogKNi-EDA = 12.33 ± 0.06） was obtained. In addition, an interesting tetranuclear complex [Nin（EDA）4]·2CH3CH2OH-9H2O was obtained unexpectedly in alcohol-water solution and characterized by X-ray crystallography and electrospray ionization mass spectra （ESI-MS）. It is found that EDA acts as a pentadentate ligand and performs a chelating-bridging coordination mode.
