Simultaneously Mechanically\nFlexible, Photobending,\nand Acidochromic Cyanostilbene Molecular Crystals

Molecular crystals that respond to\nmultiple stimuli are\ngaining\nsignificant attention for their potential in smart materials like\nactuators and sensors. However, imparting multiple stimuli-responsive\nproperties to a single crystal remains a major challenge. Herein,\nwe report two cyanostilbene derivative-based crystals <b>1</b> and <b>2</b>, with various responses to stimuli such as mechanical\nstress, light, acid vapors, etc. Both crystals <b>1</b> and <b>2</b> demonstrated mechanical flexibility and reversible acidochromism.\nAdditionally, crystal <b>1</b> also exhibited light-induced\nphotobending, which is ascribed to <i>Z</i> to <i>E</i> photoisomerization. Detailed structure–property correlation\nwas established to unravel distinct mechanical responses. The development\nof these multitasking crystals may find applications in multitasking\nactuators, anticounterfeiting materials, and more.