Two series of rod-like Schiff base liquid crystals with CH₂O bridge were synthesized, which have the structure of XC₆H₄N＝CHC₆H₃(Y)OCH₂C₆H₄COOC₁₆H₃₃, Y＝H, OCH₃; X＝OC_nH_2n＋1 (n＝1～12, 14, 16), Me, F, Cl, Br. Their mesogenic behaviors were studied with DSC and polarized optical microscopy. These results showed that the change of end substituents X and side substituent Y of benzene ring in the molecules had important effects on mesogenic properties of these liquid crystalline compounds.

Key words: liquid crystal, Schiff base, CH₂O bridge, smectic A phase, smectic B phase