Lignin, as a renewable source of aromatics has garnered interest for several applications. In this chapter, recent progress on the application of lignin as a component in thermosets and thermoplastics is summarized and discussed. In the named applications, two routes for lignin valorization are typically explored, namely: a) The depolymerization of lignin to monomeric precursors. b) The direct use of pristine lignin macromolecule, or through subsequent chemical modification, as precursors. This report will focus on the latter of the two routes. The study is further refined to address lignin as a structural component and its influence on the mechanical properties of derived thermosets and thermoplastics. The challenges with using available lignin in these applications are discussed. Finally, a future outlook on the use of lignin as a component for the construction of polymeric materials is provided.