Organic photoelectrochemical transistor (OPECT) has undergone significant advancements, enabling an effective synergy between organic electronics and photoelectrochemistry, contributing to opto-logic gates, neuromorphic emulation, and biological detection. However, feasible OPECT operation is still quite limited and the associated technology is evolving. This study introduces a self-enhancement OPECT operation facilitated by triple-functional stimuli-responsive organic molecules (SROM). The representative SROM sensitizes the photogate to selectively recognize the chosen target, where the reaction product serves to reengineer band alignment, resulting in a self-enhanced OPECT modulation. We further leverage this effect to implement highly selective detection of sulfite. The findings of this work bridge the gap between OPECT and SROM, demonstrating the significant potential of SROM in a unique OPECT operation and implementation.