This book is about the mesogens or liquid crystals which are formed via schiff base linkers. liquid crystals are the considered as the fouth state of matter. liquid crystals may be described as condensed fluid state with spontaneous anisotropy. the liquid crystalline state is a fourth state of matter that mixes the properties of both the liquid and solid states and intermediate between the two in many of its property. liquid crystals combine a kind of long-range order with the ability to form droplets and to pour. they also exhibit properties that are found in neither liquid nor solid. schiff base (-ch=n-) group has found to be very effective in rod shaped and columnar shaped liquid crystals. the various investigations and pom techniques revelaed the sma, smc and other enantiotropic mesophases.