In Japan, Otani produced the first lignin-based carbon fiber in 1965 using lignin sulfonate by dry and wet spinning . Unfortunately, the mechanical properties were unsatisfactory. Later, researchers found that the critical reason for the poor mechanical properties of carbon fibers derived from lignin is that molecules of lignin-based carbon fibers have no directionality Then, the resulting material was modified by melt spinning, which resulted in improved mechanical properties . However, after Otani's attempt, various other researchers understood the potential of lignin as a precursor for carbon fibers. They also started working on the same. Overall, it was noticed that the type of lignin, extrusion process, thermostabilization, and carbonization conditions affect the properties of the resultant carbon fibers. Below, several major attempts to synthesize lignin-based carbon fibers are discussed.