Liquid crystals (LCs) are highly fluid self-assembling media revealing the complexity of physical properties as well as providing a powerful tool for multidisciplinary research. From the application point of view, the reorientation of nematics under an applied electric field is a fundamental phenomenon, which is widely used in modern technologies. The self-assembling properties of LCs are strictly linked to the shape and chemical structure of the molecules. A variety of forces influence the packing of molecules and result in a wide number of liquid crystalline phases. In addition, for chiral molecules a tendency to form helical structures appears. Interactions promoting the self-assembly of molecules into layers are very important and a strong competition between the tendencies to form layers and to twist might lead to the existence of frustrated structures such as Blue Phases (BPs), the Twist Grain Boundary (TGB) and the SmQ phases. The structures of these phases are inevitably accompanied by defects, which have a significant impact on the forming, textures and properties.
