The anti-tumor agent cisplatin is well established as an excellent chemotherapeutic agent owing to its outstanding ability to form permanent covalent adducts with DNA. The resulting inhibition of DNA replication is effective, but numerous side effects associated with its use have prompted our investigation of other transition metal (TM) systems with alternative or additional modes of activity. For example, octahedral Cr(III) complexes have the potential to behave as anti-tumor agents through the cleavage of DNA strands in a site-specific manner following photoactivation, but may also permanently adduct to DNA in a manner like cisplatin. In this presentation, both photocleavage activity and the possible formation of adducts between Cr(III) diimine complexes (e.g., cis-[Cr(tmp)(dppz)(1-MeImid)2]3+ where tmp = 3,4,7,8-tetramethyl-1,10-phenanthroline, dppz = dipyridophenazine and 1-MeImid = 1-methylimidazole) with custom-manufactured duplex primers is investigated following activation with 350 nm radiation. Experiments using liquid chromatography with electrospray mass spectrometry (LC-ESI-MS) demonstrate the photodestructive capacity of these TM complexes. Further analyses of the interactions between DNA primers and Cr(III) complexes have been conducted using both native and denaturing polyacrylamide gel electrophoresis (PAGE), wherein we are able to qualitatively assess the relative photooxidative power of multiple Cr(III) complexes via side-by-side comparisons of DNA damage. In conjunction with LC-MS, equilibrium dialysis, and steady-state emission studies using [Ru(bpy)2(dppz)]2+ (where bpy = 2,2' bipyridine) as a DNA indicator, we have also investigated the apparent ability of diimine Cr(III) complexes to associate with primers with sufficient strength to co-migrate through the polyacrylamide gel, suggestive of potential adduct formation.