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The design and synthesis of a series bent-core materials base on a 3,4¢-biphenyldiol central core containing salicylaldimine-based and two terminal tetradecyloxy tails are reported. In addition, the effects of lateral substituents (R = F and Cl) at the biphenyl core into 3¢-position are examined. These substituents have a strong influence in reducing the clearing temperatures and increasing temperature range of SmCP phase. Upon cooling process the isotropic liquid, compound SB-Cl exhibits the lowest clearing transition temperature of 180 o C and the widest SmCP phase range of 129 o C. The mesophase behaviour were investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and electro-optical (EO) measurements in the mesophase temperature range.

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Three series of novel chiral liquid crystals containing biphenyl moiety with two chiral centres (diastereomer) were synthesized and characterized. The structures and thermal phase behaviour of target compounds were characterized using 1 H nuclear magnetic resonance, mass spectroscopy, elemental analysis, differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction measurements. All the compounds exhibit enantiotropic mesomorphic behavior. In this case, the chiral liquid crystalline molecules bearing the shorter length of alkyl chain (m = 3 and 4) show a mesomorphic dimorphism SmA*-N* and the analogous compounds bearing the longer length of alkyl chain (m = 5 and 6) exhibit only one SmA* mesophase. Furthermore, the potential of SmA* mesophase for electro-optics applications exploiting the electroclinic effect was explored. The electro-optical properties of the SmA* phase, such as voltage-transmittance effect, electroclinic effect, and electro-optical response were also measured. As a consequence, the correlation between their electrooptical properties and chemical structures of these compounds were investigated.

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