Modulating Bond Order and Aromaticity in Dual‐BN‐Bonded Dihydrophenazine for Multi‐Stimuli Responsiveness

Abstract Smart molecules possess the ability to perceive and respond to external stimuli. However, most currently existing smart molecules only showcase simple binary responses to individual stimuli. To enhance molecular stimulus‐responsiveness, we developed a dynamic molecule, 5,10‐bis(dimesitylboryl)‐5,10‐dihydrophenazine ( BNNB ). This molecule integrates two dynamic units: dihydrophenazine with adjustable aromaticity and BN bonds with tunable bonding order, enabling greater versatility. BNNB undergoes three‐stage conformational changes through the mono‐ or di‐twisting of the BN bonds and the planarization of the dihydrophenazine, demonstrating conformation‐driven multilevel responsiveness to multiple stimuli. The dynamic modification of molecular conformations leads to pronounced changes in absorption and fluorescence, resulting in noticeable thermochromism , mechanochromism , and electrochromism , as well as exhibiting force‐induced thermally activated delayed fluorescence and triple fluorescence emission arising from photoisomerization . These findings establish an integrated approach to achieving multi‐stimulus and multi‐level responses, paving the way for the development of multifunctional and multimodal responsive systems based on single‐molecule designs.