Textiles for cold-weather activities can be designed by integrating photothermal agents into the fabrics to harness solar light for textile heating. However, traditional photothermal agents (e.g., graphene) require tedious synthesis procedures and the use of harsh chemicals while still producing a low yield, unknown toxicity, and primarily black colour. By contrast, melanin has excellent photothermal properties, simple and cost-effective synthesis, biocompatibility, and is environmentally benign. Melanin also potentially renders textiles with pigmentary colours (black or brown) or structural colours (red, blue, yellow etc.), anti-UV, and anti-bacterial properties, and photo- and thermal-stability. All of these are essential for outdoor-use textiles but remain underexplored. This project proposes to unify melanin's unique mixture of properties to develop multifunctional melanised textiles. It will first establish structure-function relationships to understand the influences of melanin’s chemical compositions, morphologies, and structural colours on its photothermal properties. The established relationship will inform the synthesis of high-performance melanin and guide the design of melanin-based thermal management textiles with varying structural colours. The concepts demonstrated in this project will test fundamental hypotheses while producing and guiding future production of bioinspired materials based on melanin.