Unveiling Volcano‐Type Trends in SOCT‐ISC Photosensitization: Energy Gap Law‐Guided Strategy for Efficient Photodynamic Therapy

intersystem crossing from the charge-separated (CS) state and CS-state charge recombination via internal conversion. The CS-state energy serves as a key descriptor dictating this balance. By modulating the donor strength of the substituents, we optimized the CS-state energy and identified TCy-Pyr, a molecule near the volcano apex. TCy-Pyr exhibits outstanding photodynamic performance, with in vitro and in vivo anticancer efficacy surpassing conventional benchmarks. It also displays aggregation-induced targeting behavior, promoting selective tumor accumulation. This work elucidates the excited-state dynamics in SOCT-ISC systems and establishes a rational design strategy to overcome performance bottlenecks in photosensitizer development.