Coloration is one of the most striking features of organisms in Nature and is associated to a breadth of biological functions, from visual signaling, photoprotection to detoxification. Animals and plants achieve such a diversity of tints and shades by using both structural (physical) and pigmentary (chemical) mechanisms. While these two mechanisms were classically studied rather independently, the recent years have shown that they could act in concert at the scale of subcellular organelles. Because pigment organelles can vary in content, shape, size, density and position, they bring together physical (scattering) and chemical (absorption) processes. In technological fields, these features have been repurposed for designing more efficient optical devices and new color-changing materials. Pigment organelles also hold a central position in the intracellular and physiological environment, as exemplified by the number of pathologies in which they are involved. Studying the integrative biology of pigment organelles is therefore key to understand their optical activity in relation with their many biological functions and technological applications. In this introductory presentation, we highlight how comparative, multiscale and interdisciplinary studies, led by ecologists and cell biologists to physicist and chemists, have provided a framework to unravel the proximal and ultimate causes of coloration from spiders and cephalopods, up to humans and plants. We also point out the major gaps and key questions in the pigment organelle field that should be addressed in the coming years via a collaborative effort of scientists from all disciplines.