Visible‐Light‐Driven Fluorescence Turn‐on Photoswitches With Near Quantitative Photocyclization Yield

Photoswitchable fluorescent materials have gained significant attention for their potential in advanced information encryption and anti-counterfeiting applications. However, the common use of UV light to trigger the isomerization processes leads to photobleaching and poor fatigue resistance. Visible-light-driven fluorescent photoswitches are highly desirable, but achieving high cyclization yield remains challenging. Herein, it is reported that all visible-light-driven turn-on fluorescence in dimethoxyphenyl functionalized diarylethene isomers. The open-ring form of o-DMPB and p-DMPB exhibits near quantitative conversion yields (up to 94%) under 405 nm visible light, attributed to the strong electron-donating character. In contrast, the meta isomer m-DMPB shows limited response to visible light, with a ring-closing yield of 22%. Furthermore, all photoswitches display good thermal stability, photostability, and fatigue resistance. Notably, o-DMPB demonstrates promising applications in anti-counterfeiting, information encryption, and photorewritable patterns. This work provides a valuable strategy for the development of high-performance fluorescent photoswitches.