Improvements have been made to chemotherapies because drugs are still not reaching the tumor site at effective doses and are often associated with high systemic toxicities and poor pharmacokinetics. The nanotechnology allows more effective and less toxic chemotherapy. It has been shown that, many anticancer drugs are not able to penetrate more than 40-50 mm (equivalent to combined diameter of 3-5 cells from the vasculature). These defects lead to incomplete tumor response, multiple drug resistance and therapeutic failure. The best way to increase the efficacy and reduce the toxicity of a cancer drug is to direct the drug to its target and maintain its concentration at the site for a sufficient time for therapeutic action to take effect. Cu(II), Zn(II) and mixed Cu(II) /Zn(II) nano complexes center on opportunities for improving this process. Nano complexes of bioactive ligands had been prepared and spectroscopically characterized. The electron microscopic data confirmed the nanoform of these complexes in the range (12.2 – 85.0 nm). Invitro antitumor activity of the complexes had been studied against breast cancer cell lines and the IC50 values were detected to show that the order of the cytotoxic effect was complex (4) (Cu(II) acetate) > complex (1) (Cu(II) chloride) > complex (2) (mixed Cu(II)/Zn(II) acetate) > complex (3), (Zn(II) acetate). The invivo cytotoxicity of the complexes showed that, the complexes have no side effects after six weeks was confirmed by clinical and histopathological studies. The results augur well for breast cancer treatment.