Redox-Activated Electronic Bridges Enabling Selective Photophysical Coupling via Quantum Dot–Hydrogen-Bonded Organic Framework S-Scheme Heterojunction

The precise regulation of photophysical interaction between multiple emissive domains remains a fundamental challenge in the design of advanced luminescent materials. Here, a quantum dot-hydrogen-bonded organic framework (QD-HOF) assembly is developed in which the glutathione redox pair functions as a redox-activated electronic bridge to program interdomain coupling. Reduced glutathione establishes an efficient bridging pathway between CdTe quantum dots and triazine-based TB-HOF, activating dual emissive channels and generating a pronounced ratiometric photoluminescence response. In contrast, oxidized glutathione preferentially interacts with the framework domains and fails to complete the bridging pathway to the quantum dots, resulting in selective amplification of HOF emission while maintaining the decoupled state of the quantum dots. This redox-state-dependent switching of photophysical coupling topology enables reliable molecular discrimination through dual optical outputs, including ratiometric fluorescence and complementary colorimetric responses. Supported by combined spectroscopic and theoretical analyses, this work identifies redox-activated molecular bridging as a general mechanism for programming selective photophysical communication between discrete emissive domains, establishing a conceptual framework for dynamic interface regulation in multiemissive assemblies.