A series of mono and bi-nuclear Fe(III), Ni(II), Cu(II) and UO2 (II) complexes have been prepared from reaction of the metal salts with N',N"'-(1E,2E)-1,2-diphenylethane-1,2-diylidene)bis(2-aminobenzohydrazide); (L). Characterization of ligand and its metal complexes were assigned. An octahedral geometry has been proposed for all complexes except Cu(II) perchlorate complex which adopted square planar geometry. To through a light on the probability of structure changes with gamma-irradiation, powder samples of the complexes [Fe-2(L)Cl-6(H2O)(2)]center dot 4H(2)O (1); [Ni(L)(H2O)(2)](NO3)2 center dot 9H(2)O (3); [Cu-2(L)(OH)(2)(H2O)2](ClO4)(2) (5) were exposed to high energetic gamma-rays at 100 kGy dose (hereafter referred to as (1A, 3A, 5A). The analytical, FT-IR, UV/Vis., EPR, thermogravimetric/differential thermogravimetric (TG/DTG), magnetic susceptibility, molar conductance, molecular modeling and X-ray diffraction are applied and their results are analyzed before and after irradiation. Furthermore, the in vitro antimicrobial activity of the complexes against Staphylococcus aureus as Gram-positive strain, Escherichia coli as Gramnegative strain and antifungal Candida albicans was performed for both unirradiated and irradiated samples. The obtained results revealed that the irradiated complexes were affected, but not greatly by the utilized gamma-irradiation dose. (C) 2020 Elsevier B.V. All rights reserved.