Enhancing Emission Efficiencies Through Side‐Chain Engineering of Luminogens to Control Molecular Motion.

Controlling the efficient emission of organic luminogens in both monomeric and various aggregated states remains a challenging task. In this work, the motion of an organic luminophores is synergistically regulated by introducing side alkyl chains with appropriate length and the aromatic rotor triphenylamine. This study finds that the incorporation of alkyl chains not only increased the rotational barriers in the molecule, but also influenced the packing modes. The as‐prepared organic luminogen, FIMPA‐C6, exhibited bright emissions in solution, polymorph, and amorphous states. Furthermore, the emission of FIMPA‐C6 can be widely tuned from yellow to deep red in different aggregated states. The exceptional luminescent properties of FIMPA‐C6 make it a promising functional dye for cellular imaging applications. [ABSTRACT FROM AUTHOR]