The excited-state properties of [(L)(4)M-II(dpp)Ru-II(bpy)(2)](PF6)(n) (bpy = 2,2'-bipyridine; dpp = (2,3-bis(2-pyridyl)pyrazine); (L)(4)M-II = (NH3)(4)Ru-II (n = 4) Or (CN)(4)Fe-II (n = 0)) have been investigated by steady-state and time-resolved picosecond and nanosecond transient luminescence and absorption spectroscopic methods. The [(NH3)(4)Ru-II(dpp)Ru-II(bpy)(2)](4+*) complex is nonemissive in room-temperature H2O solution. Picosecond laser flash photolysis of [(NH3)(4)Ru-II(dpp)Ru-II(bpy)(2)](4+) reveals the formation of a trans lent sp cc ies th at decays exponentially (tau = 290 (+/-80) ps) independent of excitation wavelength. The excited-state behavior of [(NC)(4)Fe-II(dpp)Ru-II(bpy)(2)]* display a complicated dependence on excitation wavelength. Following 591-nm pulsed laser excitation into the (1)[(d pi)(Fe)(5)(pi*)(dpp)(1)]<--(1)[(d pi)(Fe)(6)] metal-to-ligand charge transfer (MLCT) band, a short-lived transient is formed with tau < 80 ps. Laser excitation at 354.7 nm into the (1)[(d pi)(Ru)(5)(pi*)(bpy/dpp)(1)]<--(1)[(d pi)(Ru)(6)] MLCT transition produces a transient species with tau > 200 ns. One explanation for the wavelength-dependent photophysics of the [(NC)(4)Fe-II(dpp)Ru-II(bpy)(2)] is that the Fe-II metal center undergoes a low-to high-spin interconversion following (1)[(d pi)(Ru)(5)(pi*)(bpy/dpp)(1)]<--(1)[(d pi)(Ru)(6)] excitation, a process not accessible via direct (1)[(dst)(Fe)(5)(pi*)(dpp)(1)]<--(1)[(d pi)(Ru)(6)] excitation.