The present research work involves the nature of interaction between the Ru(II) complex and inorganic peroxides in the absence of excitation by light photons. We synthesized a photosensitizer, ([Ru(dcbpy)(2)(biq)]Cl-2 center dot 3H(2)O) and studied its thermal degradation in the presence of inorganic peroxides (hydrogen peroxide, peroxomonosulfate and peroxodisulfate). Progress of the thermal reaction between the Ru(II) complex and each peroxide in 0.5 M H+ solutions was followed spectrophotometrically by monitoring the disappearance of the Ru(II) complex at its maximum absorbance (lambda = 514 nm). The reactivities of the peroxides were compared and suitable mechanisms proposed.