Angew. Chem. Int. Ed. Engl. 59 (2) 896-902 [2020-01-07; online 2019-11-22]
The design of turn-on dyes with optical signals sensitive to the formation of supramolecular structures provides fascinating and underexplored opportunities for G-quadruplex (G4) DNA detection and characterization. Here, we show a new switching mechanism that relies on the recognition-driven disaggregation (on-signal) of an ultrabright coumarin-quinazoline conjugate. The synthesized probe selectively lights-up parallel G4 DNA structures via the disassembly of its supramolecular state, demonstrating outputs that are easily integrable into a label-free molecular logic system. Finally, our molecule preferentially stains the G4-rich nucleoli of cancer cells.