Near-infrared (NIR) light enables a wide range of applications, such as bionic perception, artificial vision systems, but NIR-responsive optoelectronic devices remain underexplored. In this work, we suggest a photonic synaptic transistor based on a flash-memory architecture. NIR-absorbing polymer and Al₂O₃ are employed as the photoactive layer and tunneling dielectric, respectively. Upon 1200 nm NIR light illumination, electron–hole pairs are generated in the polymer. The photogenerated holes tunnel through the Al₂O₃ layer into the organic semiconductor channel, while the electrons remain trapped in the floating-gate region. This optically induced charge transfer and trapping enable synaptic-like functions, including EPSC, PPF, and long-term potentiation/depression. Leveraging wavelength-selective NIR absorption together with non-volatile conductance modulation, this work suggests a pathway toward NIR-responsive optoelectronic/neuromorphic computing applications.