The document discusses liquid crystals, which have orientational order and properties that are anisotropic. Liquid crystals are classified as lyotropic, polymeric, or thermotropic depending on how they are formed, and thermotropic liquid crystals can exist in nematic, cholesteric, or smectic phases. The molecular structure and chemical composition of liquid crystal molecules, including components like aromatic rings and terminal groups, determine the physical and optical properties exhibited in each liquid crystal phase.