Solubility behaviors of binary HFC-125 (CF3-CF2H), HFE-125 (CF3-O-CF2H), HFC-143a (CF3-CH3), and HFE-143a (CF3-O-CH3) systems with room-temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) have been studied using a gravimetric microbalance method from (283 to 348) K and/or volumetric and cloud-point methods. Vapor-liquid equilibrium (VLE) data for HFC-125 + [emim][Tf2N] and HFE-125 + [emim][Tf2N] systems have been well correlated with our equation-of-state (EOS) model, which predicted vapor-liquid-liquid equilibria (VLLE) for both of these binary systems, and the VLLE have been experimentally proved. As for the binary systems of HFC-143a + [emim][Tf2N] and HFE-143a + [emim][Tf2N], only VLLE experiments have been made, and partial miscibility (temperature and composition: VLLE-Tx) data are well correlated with the NRTL (nonrandom two-liquids) activity model. While the immiscibility gap of the HFC-125 binary system is smaller than that of the HFE-125 system, the immiscibility behaviors for the HFC-143a and HFE-143a systems are opposite; the HFE-143a system is more soluble.