We report the structure, electrochemistry, and isomerization kinetics for [Ru(bpy)(biq)(OSO)](PF6), where bpy is 2,2'-bipyridine, biq is 2,2'-biquinoline, and OSO is 2-methylsulfinylbenzoate. UV visible and infrared data are suggestive of intramolecular S -> O and O -> S isomerization of the sulfoxide. Cyclic voltammetry reveals evidence for isomerization triggered by oxidation and reduction. Of particular note is the variation of the S -> O isomerization rate constant in different solvents. The rates were found to be 3.2 (+/- 0.4) s(-1) in propylene carbonate, 0.80 (+/- 0.03) s(-1) in acetonitrile, and 0.26 (+/- 0.01) s(-1) dichloromethane.