Time-resolved emission studies have been performed on a series of covalently linked Ru(bipyridine)(3)-phenothiazine complexes. The emissive Ru(bipyridine)(3) metal-to-ligand charge-transfer (MLCT) excited state is quenched by electron donation from a phenothiazine (PTZ) donor. The rates of electron transfer (ET) to the MLCT states from the PTZ donor have been analyzed in terms of Marcus theory, in which each phenothiazine acts independently of other phenothiazines in the complex. Reaction energetics were determined from electrochemical data for Ru(2+/1+) and PTZ(1+/0) reduction potentials and MLCT state energies. Quantitative agreement was found between the model’s predictions and measured ET times. The results are compared to those obtained for the analogous electron transfer leading to charge separated state formation in a related donor-chromophore-acceptor system.