4'-(2,3 Dihydroxypropoxy) diphenyl 4-oxy-hexanoic acid and 4'-(2,3 dihydroxypropoxy) diphenyl 4-oxy-undecanoic acid have been synthesized and analyzed by IR and NMR experiments. The liquid crystalline character and the phase transitions of these two acids have been studied by differential scanning calorimetry (DSC) and variable temperature X-ray diffraction (VTXRD). These two liquid crystalline monomers are designed to be flexible, rigid and polyfunctional, so that they can be used in the synthesis of new macromolecules with side chain liquid crystals.