series of unsymmetrical liquid crystal dimers containing imine and cholesteryl moieties interconnected by 11-oxyundecanoyl were reported, which have the structure of XC₆H₄N＝CHC₆H₄OC₁₀H₂₀- COOCh* [X＝OC_nH_2n＋1 (n＝1～12, 14), F, Cl, Br, CH₃]. The target compounds were characterized with 600 MHz ¹H NMR and elemental analysis. Their mesomorphic properties were studied with polarizing optical microscopy and differential scanning calorimetry. The results showed that all of these dimesogens exhibited a cholesteric phase. For these dimesogens containing terminal alkoxy chain (X＝OC_nH_2n＋1), some also showed the smectic A phase. And it was discovered that, as the length of terminal alkoxy chain increased, the clearing points of these dimesogens decrease slowly, but the entropy change (ΔS＝ΔH/T) of these dimesogens from the cholesteric phase to isotropic liquid had an obvious odd-even effect. At the same time, the influences of the terminal substituent group X on the stability of the cholesteric phase were studied and it was discovered that the sequence of stability was: MeO＞Cl＞Br＞Me＞F. The results confirmed that the change of the terminal substituent group has a remarkable influence on the phase transition temperatures as well as the mesomorphic behavior.

Key words: liquid crystal, imine, cholesteryl, smectic A phase, cholesteric phase, odd-even effect