Lignin, a naturally abundant biopolymer, has garnered significant interest due to its unique chemical structure and its applicability in various industries, such as biomedical and automotive. Among various chemical modifications, the Mannich reaction, which introduces amine groups into the lignin structure, has gained prominence. This functionalization enhances lignin’s versatility, making it suitable for advanced engineering, biomedical, and environmental applications. The present study emphasizes lignin’s functionalization through amination, particularly via the Mannich reaction, exploring its relevance in producing bio-based materials with enhanced properties.