A new tetradentate Schiff base, 3-[(Z)-2-piperazin-1-yl-ethylimino]-1, 3-dihydro indol-2-one was synthesized by the condensation of isatin(Indole-2,3-dione) with 1-(2-aminoethyl)piperazine(AEP). Its complexes with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), UO 2 (VI) and Th(IV) have been synthesized and characterized by microanalysis, conductivity, UV-visible, FT-IR, 1 H NMR, TGA and magnetic susceptibility measurements. The complexes have 1:1 metal to ligand stoichiometry. The complexes of Cu(II) and Th(IV) are 1:1 electrolytes whereas the complexes of Co(II), Ni(II), Zn(II), Cd(II), Hg(II) and UO 2 (VI) are nonelectrolytes. The spectral data revealed that the ligand acts as a neutral tetradentate, coordinating through the azomethine nitrogen, two piperazine nitrogen atoms and carbonyl oxygen. Octahedral geometry for Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) complexes and a coordination number of 8 for UO 2 (VI) and Th(IV) complexes are proposed. The ligand and its metal complexes were screened for antibacterial activity against Bacillus subtilis, Staphylococcus aureus (S. aureus), Escherichia Coli (E.Coli) and Pseudomonas aeruginosa and the complexes are more potent bactericides than the ligand. The anthelmentic activity of the ligand and its complexes against earthworms was also tested.