Green chemicals refer to environmentally friendly substances derived from renewable sources such as biomass, plant oils, lignocellulosic material, carbon dioxide, and green hydrogen. Designed to minimize hazardous waste and improve sustainability, these chemicals span applications from pharmaceuticals and agriculture to construction and energy. They contribute significantly to lowering greenhouse gas emissions, enhancing water and soil health, reducing energy usage, and supporting industrial decarbonization. Use cases include biodegradable plastics, natural pesticides, bio-based solvents, and low-VOC coatings. Key technologies involve bioethanol, PLA, PHAs, and green hydrogen, though challenges remain around cost, scalability, and feedstock logistics.