Lignin is a complex and abundant biopolymer derived from plant cell walls and has garnered significant attention in the field of materials science. This study examines the functional characteristics and process parameters that lignin uses to help form films, emphasizing the material’s biocompatibility, biodegradability, and renewable resource status. Strong intermolecular interactions are made possible by the intrinsic aromatic structure and functional groups of lignin, which enhance film cohesion and stability. To improve the performance of the films, lignin is also being added to composite films along with other biopolymers like chitosan and cellulose. According to the results, lignin-based films show promise for several uses, such as coatings, packaging, and biomedical devices. This study expands our knowledge of lignin’s function in the production of sustainable materials and creates new opportunities for environmentally friendly film innovation. The cell walls of terrestrial plants contain the alkyl-aromatic polymer lignin. In addition to giving plants structure and stiffness, lignin acts as a naturally occurring, very powerful barrier against microbial invasion and facilitates the passage of water and nutrients through plant tissues. The components of lignin can differ significantly among plant species, resulting in a great deal of variation in the chemistry and structure of lignin. Despite nearly a century of research and development aimed at turning lignin into valuable products, it is still largely wasted and burned for heat and power in most existing and planned biorefinery contexts. Nonetheless, there has been a noticeable upsurge in the last 10 years in the search for effective lignin valorization techniques. This has been fueled by advances in our knowledge of the chemistry, structure, and plasticity of lignin. This chapter lays the groundwork for the remaining chapters in this book by providing an overview of the lignin structure aspects that are currently understood.