**1. Introduction**

The research on carbonaceous mesophase can be traced back to the 1960s, when Books and Taylor found there was liquid-crystalline phase (i.e., mesophase spheres) in the thermal conversion of carbonaceous feedstocks, which opens a new era in the research of liquid-phase carbonization and the development of carbon material industry [1]. Up to now, carbonaceous mesophase has been studied for more than 50 years and has always been the research hotspot and focus in the field of carbon materials [2–5]. Mesophase pitch has long been recognized as a liquid crystal in a defined temperature range (e.g., 200–400°C) and exhibits both lyotropic and thermotropic nature, which is different from ordinary polymers and isotropic pitch [2]. It is well known that the mesophase pitch with a nematic liquid crystal structure possesses an easily graphitizable characteristic and can be preferentially aligned under mechanical force shearing after melting; thereby it is regarded as a basic raw material for preparing high-performance carbon and graphite materials with controllable structure of forming an ordered graphite, which provides a feasible route to prepare graphite-like materials [2]. In addition to the high carbon yield and potential price advantage (owing to the relatively low cost of carbonaceous raw materials) of

#### **Figure 1.**

*Main promising applications of carbonaceous mesophase as an excellent precursor for making a wide variety of industrial and engineering carbon products.*

mesophase pitch, it has become a high-quality precursor material for fabricating high-performance and multifunctional carbon materials as shown in **Figure 1**, such as mesophase pitch-based coke, needle coke, high-power graphite electrodes, mesocarbon microbeads (MCMBs), mesophase pitch-based carbon foam, mesophase pitch-based carbon fibers with high modulus and thermal conductivity, good binder and impregnating agent for high-thermal conductivity carbon-based composites, etc. Therefore, there is no doubt that mesophase pitch occupies a pivotal and irreplaceable position in various fields, such as defense, military, aerospace, cutting-edge technology, high-end industrial manufacturing, etc. [2, 3, 5].
