Self-contained photo-acid generators with high quantum yields triggered by photo-cyclization.

We present a novel series of neutral photo-acid generators (PAGs) based on carbazole derivatives. A photo-induced 6π-electrocyclization reaction of carbazole derivatives triggers the subsequent release of halogen acids. With UV irradiation, PAGs spontaneously release acid molecules quantitatively forming polyaromatic compounds. To our knowledge, it is considered the highest quantum yield (over 85%) among Brønsted PAGs.