CA9 and colonic neoplasm: The incorporation of the carbonic anhydrase IX (CAIX)-targeting group into phenylpyridine-, difluorophenylpyridine-, and phenylquinoline-based Ir(iii) complexes was investigated as an approach for the treatment of HT29 colon cancer cells via PDT.233 Upon irradiation with light (λex at 425 nm), phenylquinoline-based Ir9 induced pyroptosis under hypoxic conditions.