Self‐Enhanced Dual‐Emissive Electrochemiluminescent Metallacages Combining Aggregation‐Caused Quenching and Aggregation‐Induced Emission Dyes

Aggregation‐caused quenching (ACQ) and aggregation‐induced emission (AIE) represent two opposite but incomplete paradigms in aggregation‐dependent luminescence, in which efficient emission is confined to either dispersed or aggregated state. Bridging these regimes within a single system remains challenging. Herein, we report a metallacage (MC)‐based electrochemiluminescent (ECL) system, in which a tetraphenylethene (TPE)‐based pyridyl ligand and π‐extended conjugation derivatives are bridged together to act as AIE and ACQ chromophores within a single structurally well‐defined framework. The discrete cage architecture controls chromophore orientation, π–π interactions, and donor–acceptor characteristics, achieving dual‐emission from ACQ chromophore in the dispersed state and AIE chromophore in the aggregated state. Moreover, a platinum(II) complex serves as not only the rigid bridging node but also as catalytic center, which promotes the reduction of S 2 O 8 2– coreactant to generate sulfate anion radical (SO 4 •– ), establishing a self‐enhanced ECL paradigm. In addition, aggregation‐dependent redistribution between two emissive channels enables ECL activity in both dispersed and aggregated states. The aggregate formed at a water fraction of 40% shows a 4‐fold intensity enhancement relative to the dispersed state. These results demonstrate MC can reconcile ACQ and AIE effects within a single system and provide tunable ECL luminophores for multiplexed sensing and imaging.