摘要： From a historical perspective, the first high pressure experiments were carried out soon after the discovery of liquid crystals, although the field became more active much later. Despite being considered as equivalent thermodynamic variables, temperature (T) and pressure (P) act differently on liquid crystals (LC), with the former affecting the rotational and vibration energy dependent parameters, and the latter altering the intermolecular distances. This feature, in combination with the fact that relatively low pressures bring about significant changes in the properties of LCs, has provided impetus for the studies described here. These investigations have not only augmented the knowledge on LCs obtained at atmospheric pressure, but have provided valuable insights into the understanding of complex fluids (Chandrasekhar and Shashidhar, 1979; Pollmann, 1999; Urban, 2014); the studies have been carried out using apparatus such as optical transmission, DTA, calorimetry, dielectric, NMR, XRD, volumetry, and Raman, detailed in these articles. For the description of the structures of the LC mesophases, numbering more than 40, the reader may refer to the article.