A novel binuclear complex of niobium(V) containing two curcuminato, and two bridging chloro ligands, was synthesized and characterized by means of nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR), Fourier-transform infrared spectroscopy, inductively coupled plasma–atomic emission spectroscopy, thermogravimetric analysis, and ultraviolet–visible (UV–Vis) spectroscopy. Di-µ-chlorobis[dichlorocurcuminatoniobium(V)] dihydrate was screened for medicinal applications, including its antioxidant activity, antibacterial activity, and an in vitro test on human breast cancer cell line (MCF-7) and normal fibroblast cells. The results showed that complexation with curcumin positively influenced the anticancer, antibacterial, and antioxidant activity of niobium(V) chloride. Di-µ-chlorobis[dichlorocurcuminatoniobium(V)] dihydrate showed significant antibacterial activity against Gram-negative Escherichia coli and Pseudomonas aeruginosa, in comparison with reference drugs including tetracycline, chloramphenicol, and ampicillin as positive controls. Antioxidant activity tests revealed radical scavenging activity of the complex at a wide range of concentrations comparable to that of ascorbic acid as standard. Finally, it was found that the cytotoxicity of the complex against cancer cells was reasonably higher than normal fibroblast cells.