Solid‐State Emission and Aggregate Emission of Aroyl‐ S,N‐Ketene Acetals Are Controlled and Tuned by Their Substitution Pattern

Aroyl‐S,N‐ketene acetals are a novel highly diverse class of aggregation‐induced emission fluorogens (AIEgens) with a plethora of interesting properties. An expanded compound library of more than 110 dyes set the stage for the first qualitative control and tuneability of all aspects of their photophysical properties. The interplay of substituents not only allows tuning and prediction of the emission color, but also of the intensity, and quantum yields both in solids and in the aggregated state; these can be rationalized by scrutinizing intermolecular interactions in the crystalline solid state.