Formation of a DNA-bound heterobimetallic complex involving Ru(bpy)(2)tpphz(2+) (tpphz = tetrapyrido[3,2-a: 2',3'-c:3",2"-h:2",3"-j]phenazine) and Cu2+ proposed. The monomeric Ru(bpy)(2)tpphz(2+) is highly luminescent in B-DNA at [DNA-P]/[Ru] = 50, 10 mu M Ru. Upon addition of Cu2+, luminescence loss and spectral shifts consistent with Cu2+ complexation and strong associational quenching are observed. Formation of a Ru(bpy)(2)tpphz(2+)/Cu2+ DNA complex which places one metal center in the major groove and the other in the minor groove on the opposing side of the helical axis is proposed. [GRAPHICS]