Approximately 5 % of all organic compounds are transformed at their melting point into liquid crystals-thermodynamically stable, anisotropic liquids which in contrast to isotropic melts appear turbid and are also known as mesophases. Such melts are classed as smectic, nematic, and cholesteric liquid crystalline phases, depending upon the arrangement of the constituent molecules. The discovery of numerous potential applications during the past ten years has awakened the study of liquid crystals from its former slumber as a physical curiosity and placed it in the limelight of the scientific stage. Uses in display systems for measured values and for computer and process data, as well as for remote controlled timetables, for windows of variable light-transmission, etc., appear particularly promising. Not only black-and-white contrasts are now possible but also color production.

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One unsymmetricly p,p′-disubstituted trans-stilben and more than 60 new phenylbenzoates are described (Tab. 1). These compounds show partly enantiotropic, partly monotropic nematic behaviour. Some low melting substances and especially eutectic mixtures of this class of compounds are useful as room-temperature nematic, colourless liquids for electro-optical applications.

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