A phosphoryl Ru(II) polypyridyl complex was prepared in a one-pot process. Theoretical analysis suggests that the phosphoryl ligand may be viewed as a strong σ-donor anionic phosphine L-type ligand. State-of-the-art free-energy profile calculations on the excited states demonstrate that both favorable thermodynamic and kinetic factors are responsible for the remarkable room temperature luminescence properties of the phosphoryl complex.