A new diferric complex, Fe 2 L b , in which a DNA intercalator (acridine) is linked to a precursor diferric complex (Fe 2 L a ), has been designed and synthesised as a hydrolytic cleaving agent of DNA. Compared with Fe 2 L a (without the DNA inter- -(3,5-bis{[(2-hydroxybenzyl) (pyridin-2-yl)methylamino]-methyl}-4-hydroxybenzyl)pentanamide] leads to a 14-fold increase in the cleavage efficiency of plasmid DNA due to the binding interaction between DNA and the acridine moiety. The interaction has been demonstrated by UV/Vis absorption, CD spectroscopy, viscidity experiments and thermal denaturation studies. The hydrolytic mechanism is supported by evidence from T4 DNA ligase assay, reactive oxygen spe-