A ternary copper(II) complex, [Cu(Dpq)(Gly)(H 2 O)]•NO 3 •1.5H 2 O (Dpq=dipyrido[3,2-d:2',3'-f]quinoxaline, Gly=glycine), has been synthesized and structurally characterized. The complex crystallized in a triclinic system with space group P-1, a=6.6979(9) Å, b=7.6351(10) Å, c=18.980(2) Å, α=85.815(2)°, β=88.182(2)°, γ= 71.203(2)°. The five-coordinate copper(II) center is a distorted square pyramid. Absorption spectra, fluorescence spectra and CD spectra showed that there were interactions between the copper complex and DNA through a groove binding mode. The complex exhibited efficient DNA cleavage activity at micromolar concentration in the presence of ascorbate with hydroxyl radicals as the active species.