Tetraphenylethene modified perylene bisimide: effect of the number of substituents on AIE performance.

Perylene bisimide derivatives substituted with one and two tetraphenylethene moieties at 1 and 1,7-postions show distinct optical properties. The former displays characteristic emission features of perylene bisimides in solution and red emission in the aggregate state, while the latter is nonemissive in solution but highly red-emissive in the aggregate state.