Tetrazine moieties cause significant emission quenching through various mechanisms. In general, the primary quenching mechanism involves accessing the dark n-π* transition state in the tetrazine moiety. When the tetrazine moiety is conjugated with a chromophore, this access comes from the internal conversion process, termed internal conversion to dark state (ICDS). Alternatively, when access comes from energy transfer processes such as FRET or DET between tetrazine and fluorophore, the quenching process is summarized as energy transfer to dark state (ETDS). Additionally, when tetrazine is located close to a fluorophore, the electron-deficient tetrazine unit can act as a strong acceptor, causing a non-radiative electron-transferred (ET) state through the PeT mechanism. At the same time, AIEgens with highly twisted and rotational structures are well known to quench their emission through molecular motion. As one of the molecular flexibility triggering quenching states, we focused on the twisted-intramolecular charge transfer (TICT) state, in which molecules are twisted to intramolecularly separate charge between electron-rich and electron-poor moieties that cause weaker emission.