All-visible-light triggered solid-state dual-color fluorescence switching of phenanthroimidazole-based bisthienylethene

All-visible-light controlled fluorescence switching is more promising for bioimaging. Constructing dual-color fluorescent bisthienylethene (BTE) systems are quite challenging. Here, all-visible-light triggered dual-color fluorescence switching was achieved in a color-specific switching manner in a solid-state by associating the photochromic BTE core with a blue emissive phenanthroimidazole (PI) unit. Unique emission behaviour caused by J -aggregation of the coplanar PI unit was crucial, which suggested a novel strategy for constructing dual-color fluorescent photoswitching. Moreover, a turn-off fluorescence photoswitching was demonstrated in solution and PMMA films owing to the energy transfer from the PI moiety to a ring-closed isomer of the BTE moiety. Remarkably, an all-visible-light patterning application for information storage medium was developed with these compounds. BTE-P1 was successfully utilized in cellular imaging for efficient fluorescence switching. All-visible-light triggered dual-color fluorescent switching was achieved in solid state, while on/off fluorescent switching was demonstrated in solution.