Photothermal materials have been extensively researched and utilized owing to their exceptional energy conversion capabilities. However, developing dual-functional materials with both vivid coloration and efficient photothermal performance remains a significant challenge, primarily because most photothermal materials have an undesirable black appearance. Herein, colorful photothermal polycaffeic photonic crystal (PCfA PC) cotton fabric was successfully created by assembling melanin-like polycaffeic acid nanoparticles (PCfA NPs) with adjustable size and high monodispersity. The photothermal performance of the PCfA NPs enabled the developed PCfA PC cotton fabric to reach a temperature increase of 86 °C under laser irradiation at a power density of 0.298 W/cm