Two new Cobalt(II) (C1) and Zinc(II) (C2) complexes were synthesized using the one-pot reaction of their metal salts with pyridine-2,6-dicarboxylic and also, amines containing 4-aminopyridine and/or 2-aminobenzimidazole, respectively. The structure of both compounds was determined by spectroscopic methods and single-crystal X-ray diffraction. The disordered octahedral geometry was proposed for both complexes. Cyclic voltammetry measurements on the compounds showed that C1 is a redox-active compound while significant electrochemical activity did not exhibit for C2, versus Ag/AgCl under argon. The anti-proliferative effect of the compounds was studied in vitro using oxaliplatin as a standard against three cancer cell lines including a human breast cancer (MCF7), a human colon adenocarcinoma (HT29), a human lymphocyte (HL60), as well as one normal cell line human foreskin fibroblast (HFF). The remarkable inhibition effect was indicated toward MCF7 cells by C1. Therefore, the collapse of mitochondrial membrane potential (MMP) and also the generation of reactive oxygen species (ROS) were evaluated in these cells following treatment by C1. The cytostatic effect of this complex in the MCF7 3D spheroid model was depicted
