Sustainable polymer synthesis has become a significant focus in the field of materials science, aiming to reduce the environmental impact of polymer production while maintaining the performance characteristics required for various applications. Green synthesis methods, including solvent-free processes, supercritical fluid processing, and catalytic and enzymatic polymerization, represent promising alternatives to traditional polymerization techniques that rely on toxic solvents, high energy consumption, and non-renewable resources. This section explores these green synthesis methods and their application in the development of semicrystalline polymers.