Tetranuclear zinc(II) and nickel(II) complexes formulated as [M-4(bpmp)(2)(CA)(2)](ClO4)(2) (M = Zn : 1, Ni : 2) have been synthesized, where Hbpmp and H(2)CA are a multidentate dinucleating ligand and chloranilic acid, respectively. X-ray crystallography of 1.2BuCN has revealed that the phenoxide moiety from bpmp(-) bridges two Zn(II) ions, which are further connected to another mu-phenoxo zinc pair by two pi-pi stacked CA(2-) units in a double bis-bidentate fashion. Electrochemical study combined EPR techniques revealed that 1 was reduced at E-1/2 = -1.10 V in a one-step 2-electron process and the resultant two CA.(3-) radicals are, antiferromagnetically coupled.