OBJECTIVE: Chemotherapy is one of the most effective and widely used treatment types for breast cancer. The Ni(II) proline dithiocarbamate (Ni(II)ProDtc) complex has been synthesized as a potential anticancer agent with minimal systemic toxicity. The dithiocarbamate ligand, combined with the amino acid proline, holds promise as a radio chemotherapeutic target agent in tumors. The anticancer activity of a Ni(II) complex compound with a proline dithiocarbamate ligand was tested on the MCF-7 breast cancer cell line as part of a study on essential metal-based therapeutics. METHODS: Molecular docking studies identified the active sites for the estradiol-estrogen receptor-α protein. The Ni(II)ProDtc complex was synthesized and characterized using melting point analysis, conductivity measurements, UV-Vis spectroscopy, and FT-IR spectroscopy. The cytotoxicity of the complex was evaluated in vitro using the MCF-7 breast cancer cell line. RESULTS: The UV-Vis spectrum at 246 nm indicated the π→π* intraligand transition of the CS2 group, while FT-IR analysis revealed peaks at 364-457 cm-1 corresponding to the bonding between Ni and Sulfur (S) and Oxygen (O) from proline. Further, the UV-Vis spectrum displayed bands at 212 and 676 nm, and FT-IR data at 387-691 cm-1, confirming the coordination of the Ni(II) atoms with sulfur, nitrogen, and oxygen in the isoleucine dithiocarbamate ligand. In vitro, cytotoxicity tests revealed that Ni(II)ProDtc induced cell death in the breast cancer cell line, showing significant morphological changes in MCF-7 cancer cells, with an IC50 value of 315.70 µg/mL. CONCLUSION: The Ni(II)ProDtc complex was successfully synthesized and demonstrates anticancer activity in MCF-7 breast cancer cells, indicating significant potential as an anticancer agent for breast cancer.