A number of ternary systems with tow fluorinated solvent mixtures and tetrahydrofuran (THF) were studied. The perfluorinated solvent phase consisted of perfluorohexane (FC72) or perfluamine (FC3283) with hydrofluoroether (HFE7100, HFE7300, HFE7500). Hydrofluoroether was added to perfluorohexane or perfluamine to tune the fluorophilicity of the fluorous phase. The temperature dependence of the liquid-liquid equilibrium was investigated at tow different temperatures, 298.15 K and 273.15 K. The immiscibility region at 273.15 K was larger than that at 298.15 K. The NRTL and UNIQUAC models yielded good correlation for the 10 ternary systems, including FC72 + HFE7100 + THF, FC72 + HFE7300 + THF, FC72 + HFE7500 + THF, FC3283 + HFE7300 + THF, and FC3283 + HFE7500 + THF.