The spectroscopic properties of complexes denoted as Ru(tBu2bpy)~(bpy-X) '~ (R~-X) and Os('Bu2bpy)2(bpy-Y)2+ (Os-Y) are reported (bpy is 2~2'-bipyridine and tBn2bpy is 4,4'bis-(tert-butyt)-2,2'-bpy). X and Y are pairs of functional groups containing bases known to be capable of hydrogen bonding; X/Y = adenine/thymine (A/T) form double hydrogen bonds, and cytosine/guanine (C/G) can form triple hydrogen bonds. The association processes for the RuoX/Os--Y couples beariag complementary base pairs in dichloromethane have b~'e~ investigated by using ~H NMR or luminescence spectroscopy. The adenine/thymine couple is responsible t~r a low association cons-zant for ~he Ru-A. T-Os associate, ;(A ~-102 M-~, and mixtures of Ru-A and Os-T complexes do not give significant amounts of associate in solution at the highest concentrations used for spectroscopic studies (--l0 -4 M) By contrast, the hydrogen bonding interaction for the couple Ru-C/Os-G results in Ka)5x 103M '~ in dichloromethane ~t 22 :C, as evaluated by using lmninescence results before and after addition of ethanol, The photoinduced Ru-,Os energy transfer within the Ru-C'G-Os associate (exothermicity ca. 0.3 eV) could be monitored with the use of time-resolved luminescence spectroscopy and was fbund to occur with a rate constant ~:~, =9.3 x t07 s-~.