Two original series of highly fluorinated sulfamates and biphenyls having thermotropic mesophases are synthesized and their liquid crystal properties are studied by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Fluorinated sulfamates exhibit a wide mesophasic temperature ranges (48.3 – 140.5°C). However, the fluorinated biphenyls, usually described as liquid crystals, are instable and mesophases cannot be determined. The unexpected enantiotropic mesophases relationship of fluorinated sulfamates is been reported in this work. Two structural parameters are discussed, the length of both fluorinated tail and hydrocarbon linker.