Remarkable Piezochromism Of Alkoxy-Substituted D-Pi-A Quinoline Derivatives Induced By Protonation

We report two solid-emissive fluorescent dyes based on alkoxy-substituted quinoline derivatives with D-pi-A structure, which exhibit reversible fluorescent response upon protonation and deprotonation. The neutral forms exhibit negligible fluorescence changes upon mechanical force, but remarkable piezochromism with significant emission changes could be obtained after protonation, demonstrating a new strategy to manipulate piezochromism.