A series of Hg(II), Mn(II) and Co(II) complexes with 3-(2-(2-oxo-2Hchromene-3-carbonyl)hydrazono)-N-(pyridin-2-yl)butanamide (H 2 L) were synthesised. The synthesized compounds were deduced by various spectroscopic techniques. The geometry of isolated complexes was estimated by using the DFT theory. Also, Pb(II) and Cd(II) were separated by means of flotation technique. Moreover, cytotoxic, antimicrobial and anti-oxidant activities of the synthesized compounds were examined.