This research explores the valorization of rice husk lignin, a renewable and low-cost agricultural byproduct, for the development of multifunctional, eco-friendly materials and cosmetic products. Lignin, a natural phenolic biopolymer, possesses intrinsic UV-blocking and antioxidant properties, making it a promising alternative to synthetic polymers and chemical UV filters. The study focuses on synthesizing spherical lignin nanoparticles (sLNPs) and hybrid lignin nanoparticles (LNPs) by incorporating lignin using environmentally friendly methods. These nanoparticles will be characterized through advanced techniques including SEM, TEM, DLS, FTIR, UV-Vis spectroscopy, and TGA to assess their morphology, size, surface chemistry, optical properties, and thermal stability. The research evaluates their functionality in two main applications: (i) reinforcement of biodegradable films to enhance mechanical and barrier properties, and (ii) formulation of sunscreen emulsions to improve UV protection, antioxidant activity, stability, and skin compatibility. Comparative studies between lignin and hybrid nanoparticle systems aim to identify the most effective formulations. By converting rice husk lignin into high-performance nanoparticle systems, the project advances circular economy principles, reduces reliance on synthetic UV blockers and plastics, and contributes to sustainable material and cosmetic design.