We prepared new thioether-arylphosphines bearing alkyl and fluoroalkyl chains at the sulfur atom in order to use them in metal-catalyzed reactions in new reaction media, such as a fluorous biphasic system. The characterization of the new compounds is discussed and the partition coefficients in the biphasic system perfluoromethylcyclohexane-cyclohexane were determined. Fluorous thioether-phosphines reacted with [Rh(acac)(CO)2] under fluorous biphasic conditions to produce rhodium species retained in the fluorous phase with ≤2.32 ppm of rhodium loss in the organic phase. The effect of S-ponytails on the coordination properties of the new phosphines and their relation with ³¹P NMR chemical shifts were supported by DFT calculations.