Two complexes of Zn(II) and Ni(II) ions with the urea derivative, 2-benzimidazolyl-urea (BZIMU), of formulae [ZnBZIMU)(2)(H2O)](NO3)(2) (1) and [Ni(BZIMU)(2)(CH3CH2OH)(2)](NO3)(2) (2) were synthesized and characterized by their melting point, elemental analysis, spectroscopic techniques (FTIR, UV-Vis and H-1-NMR), High-resolution mass spectroscopy (HRMS), molar conductivity and thermogravimetric analysis. The crystal structures of 1-2 were determined by X-ray diffraction analysis. The antiproliferative activity of 1-2 was tested in vitro against human adenocarcinoma cell lines: cervix (HeLa) and breast (MCF-7). Their toxicity was surveyed against normal human fetal lung fibroblast cells (MRC-5). The bioactivity mechanism of 1-2 and their related analogues of copper and silver metallodrugs are rationalized by the means of computations. The antimicrobial activity of 1-2 against Escherichia coli (E. coli) is also evaluated.Graphical AbstractThe complexes [ZnBZIMU)(2)(H2O)](NO3)(2) (1) and [Ni(BZIMU)(2)(CH3CH2OH)(2)](NO3)(2) (2) (BZIMU= 2-Benzimidazolyl-urea), were tested in vitro against HeLa and MCF-7 cells. Their toxicity was surveyed against normal MRC-5 cells. The association of the microbiota with the antiproliferative activity of 1-2 was investigated against Escherichia coli.