64214 2025 eng 1 6 article Wiley-VCH Weinheim 1 -- -- -- The first push–pull quino [3]radialene fluorescent dye is reported. Herein, the novel bis(dicyanomethylene)-[3]radialene electron acceptor is connected to a benzimidazole donor. With protonation, a substantial redshift of fluorescence wavelength is observed, while the absorption maximum remains stable. This process is accompanied with an increased fluorescence quantum yield to about 70%. Further, the findings are explained by a combined experimental and theoretical approach, and it is found that vibronic coupling plays a crucial role. This study highlights the yet unexplored potential of [3]radialene-based motifs for the design of environment-responsive fluorophores. European journal of organic chemistry 10.1002/ejoc.202500669 1099-0690 urn:nbn:de:kobv:b43-642147 publish 26.09.2025 Creative Commons - CC BY - Namensnennung 4.0 International J. P. Soyka J. F. Witte A. Wiesner A. R. Krappe D. Wehner N. Alnicola B. Paulus Ute Resch-Genger S. Eigler eng uncontrolled DADQ eng uncontrolled Nanographene eng uncontrolled fluorescence eng uncontrolled Nano eng uncontrolled Particle eng uncontrolled Synthesis eng uncontrolled Characterization eng uncontrolled Advanced material eng uncontrolled Quantum yield eng uncontrolled Photophysic eng uncontrolled pH eng uncontrolled Probe eng uncontrolled Sensor eng uncontrolled Lifetime eng uncontrolled Polarity Ingenieurwissenschaften und zugeordnete Tätigkeiten Sanitär- und Kommunaltechnik; Umwelttechnik 1 Analytische Chemie; Referenzmaterialien 1.2 Biophotonik Umwelt Material Verlagsliteratur Datei für die Öffentlichkeit verfügbar ("Open Access") Wissenschaftliche Artikel der BAM Advanced Materials Bundesanstalt für Materialforschung und -prüfung (BAM) https://opus4.kobv.de/opus4-bam/files/64214/Soyka_2025_3 Radialene Fluorophores with pHSwitchable Emission and Stable Absorption Maxima.pdf