Scriabin is the most famous name in color music and the most debated. He assigned colors to keys, arranged around the circle of fifths, and wrote a light part into Prometheus: The Poem of Fire. What is disputed is the mechanism: genuine chromesthesia, or a system built from theory and theosophy?
The doubters’ evidence is real. His mapping’s tidy geometric structure looks designed; contemporaries recorded him discussing it as doctrine as much as perception; and accounts of his disagreements with Rimsky-Korsakov, a fellow color-hearer, show him defending correspondences from principle rather than experience.
The honest verdict is uncertain: possibly a synesthete, certainly a system-builder. His influence does not depend on the diagnosis; the color system shaped a century of visual music either way.