Xanthopterin hydrate is primarily used in biochemical research due to its role in pigmentation and light absorption. It is studied for its presence in the wings of certain butterflies, where it contributes to their vibrant colors and UV reflectance. This compound is also explored in the field of optoelectronics, as it has potential applications in developing bio-inspired materials for light-sensitive devices. Additionally, xanthopterin hydrate is investigated in medical research for its antioxidant properties and its role in metabolic processes, particularly in relation to pterin-related disorders. Its ability to interact with light makes it a candidate for studies in photodynamic therapy and other light-based treatments.