Three new ‘NNOO’ type tetradentate Schiff base ligands have been synthesised by the condensation of Acenaphthenequinone with essential amino acids in 1:2 stoichiometry. They were complexed with copper and structurally characterized by analytical techniques like molar conductance, magnetic studies and spectral techniques like 13C NMR, EI-Mass, FT-IR, UV-Visible spectra, EPR spectra etc. The complexes are non-electrolytes. The Schiff bases act as tetradentate ligand leading to square planar geometry around Cu (II) in all the three complexes. The electrochemical studies explain the change of structural arrangement of the ligand around Cu (II) ions. The metal complexes are subjected to DNA cleavage with pUC19DNA. The invitro antibacterial assay of the complexes against gram positive and gram negative strains indicate that they are biocidal agents.