The title complex Ni(EDTB)•2Cl•CH₃OH•C₂H₅OH [EDTB＝N,N,N',N'-tetrakis-[(2-benzimi- dazolyl)methyl]-1,2-ethanediamine] has been synthesized and characterized by elemental analysis and single crystal X-ray diffraction method. The crystal of mononuclear Ni(II) complex belongs to triclinic system with space group, P1, a＝1.0931(2) nm, b＝1.1693(2) nm, c＝1.6756(4) nm, α＝76.042(3)°, β＝88.787(3)°, γ＝72.044(3)°, V＝1.9740(7) nm³, D_c＝1.321 g/cm³, Z＝2, F(000)＝824, μ＝0.670 mm^－1. The final R[I＞2σ(I)]: R₁＝0.0611, wR₂＝0.1497 and R (all data): R₁＝0.0870, wR₂＝0.1604. The nickel(II) atom of the cation has distorted octahedral coordination geometry and is six-coordinated by six nitrogen atoms: four nitrogen atoms of the benzimidazole groups and two tertiary amine nitrogen atoms from the ligand. The superoxide dismutase mimic activity of the complex has been determined by means of modified Marklund method to show that the title complex has a high superoxide dismutase mimic activity.

Key words: nickel complex, crystal structure, superoxide dismutase mimic activity, N,N,N',N'-tetrakis- [(2-benzimidazolyl)methyl]-1,2-ethanediamine (EDTB)