A series of Schiff base type liquid crystalline crown ethers were synthesized using the intermediates 4-(4′-alkoxylbiphenyl-4-carboxyl)benzaldehyde and diaminodibenzo-14-crown-4. Their structures andproperties were characterized by elemental analysis, rotation polarmetric analysis, ¹H NMR, IR, FAB-MS, MALDI-TOF-MS, DSC and polarizing optical microscopy with a heating stage. It was found that the compounds 2,4, 8I and 8II formed liquid crystalline phase when heated to their melting points. In their liquid crystalline state, the typical chiral smectic C phase, smectic phase, cholesteric phase, nemetic phase texture can be observed. Except the compounds 2A and4A, the smectic phase temperature range increases, but the smectic-nemetic transition temperature and nemetic phase temperature decrease with the increasing in the carbon numbers of end alkoxy groups. Accordingly, the melting point (T_m) and isotropization temperature (T_i) can change regularly.

Key words: Schiff base, crown ether, thermotropic liquid crystal, synthesis, property