Equilibrium tie-line data were determined for a fluorous biphasic systems at 298.15 K. Two phase mixtures were used, consisting of a perfluorinated solvent phase using a mixture of two fluorinated solvents (methyl nonafluorobutyl ether and perfluorohexane) as well as an organic solvent phase in which the organic solvents studied were toluene, 1,4-dioxane, and dimethylformamide, respectively. Nonrandom two liquid models applied to the four ternary systems produced interaction parameters that were well-correlated with the equilibrium composition. These parameters enabled the prediction of liquid-liquid equilibrium systems containing methyl nonafluorobutyl ether and perfluorohexane. The ability to manipulate fluorous biphasic systems composed of perfluorohexane and an organic solvent with the addition of methyl nonafluorobutyl ether was examined.