AbstractA new imidazolate bridged Cu2+, Zn2+binuclear complex [(dtma) CuImZn (dtma)]ClO4· 2.5H2O taken as active site model for Cu, Zn‐SOD has been synthesized and its crystal structure determined. All the bond lengths, bond angles and the distance between Cu and Zn atoms in Cu‐Im‐Zn core of the model complex are close to those in Cu, Zn‐SOD. ESR parameters of the model complex as a function of pH show that the imidazolate bridge is stable in pH range 10–12, and is broken on Zn side at pH ∼9. With decreasing pH, the imidazole is released at pH ∼4 and the dtma ligand dissociates from the Cu containing fragm