CTSB and cancer: Inthe presence of both stimuli conditions (GSH and cathepsin B), orupon internalization into A549 and HepG2 cancer cells, compound 74 was activated to release free phthalocyanine via the cleavageof the peptide linkage and subsequent removal of the DNBS moieties,realizing 80–87% fluorescence recovery and efficient ROS generation,as a result of disaggregation of the photosensitizing units and thedisappearance of the PET effect.