Two new mercury(II) complexes (C1) and (C2) were prepared through one-pot reactions of pyridine dicarboxylic acid derivatives, aminopyridine derivatives, and mercury(II) chloride metal salt. The structures of both complexes were exactly determined by X-ray crystallography. Also, studies were done by elemental and thermal analysis, FT-IR, UV-Vis, and 1HNMR spectroscopy on them. In this research, the antibacterial effect of all compounds was evaluated against three Gram-positive bacteria namely Staphylococcus aureus, Streptococcus pyogenes and Staphylococcus epidermidis, and also three Gram-negative bacteria namely Escherichia coli, Pseudomonas aeruginosa, and Proteus vulgaris. The established antibacterial tests were including the broth microdilution method and the agar well diffusion method. S. aureus was considered as the most susceptible bacterium following treatment of the C1 (MIC=16 μg/mL, IZD=21 mm) and C2 (MIC=32 μg/mL, IZD=18 mm). Also, cytotoxicity of the compounds was studied in vitro using oxaliplatin as a standard by MTT assay against three cancer cell lines including human breast cancer (MCF7), human colon adenocarcinoma (HT29) and human lymphocyte (HL60). The strongest anti-proliferative effect of the C1 and C2 was exhibited toward MCF7 cells with IC50 values equal to 100 and 1μM, respectively
