Novel beta,beta-azo bridged diporphyrins were synthesized through 2-nitro-5,10,15,20-tetraphenylporphyrin coupled with sodium borohydride/Pd-C as a reduction system, and their structures were characterized by UV-vis, H-1 NMR, IR, mass spectra, Raman spectroscopy and elementary analysis. Their cleavage ability to pBR322 plasmid DNA had been tested by gel electrophoresis.