Today there are several thousand organic compounds that show liquid crystalline phases. All these materials have at least one thing in common; their geometrical anisotoropy. Liquid crystals possess the mobility of a fluid so that they take the shape of their containers. On the other hand liquid crystals have optical properties of a solid. One can obtain the liquid crystal phase by heating certain organic compounds (thermotropic liquid crystals) or by mixing two or more compounds (Lyotopic liquid crystals) one of which is generally polar. There are many other phases that are possible besides the three broad classes of nematic, cholesteric and smectic phases. Not all the materials have all the phases present. Liquid crystals have been found useful both in application (especially the display application) as well as in the basic and fundamental research. The liquid crystal display (LCD) in calculators and watches is now a common observation power consumption and size of the display have been important issues for their use.