An original procedure for efficient synthesis of a functionalized salen copper complex is reported. The mode of binding to DNA of the salen . Cu-II complex was investigated by viscometry as well as by absorption, circular, and linear dichroism spectroscopy. The complex can induce DNA strand breakage in the presence of a reducing agent as revealed by a plasmid cleavage assay. The spectroscopic and biochemical data indicate that the salen . Cu-II complex induces single-stranded breaks via an interaction within one of the grooves of the double helix.