Planarized and Twisted Intramolecular Charge Transfer: Small Geometric, Huge Photophysical Changes

Molecular motion plays a central role in excited‐state relaxation and fluorescence behavior of donor–acceptor systems. While twisted intramolecular charge transfer (TICT) and planarized intramolecular charge transfer (PLICT) have been extensively studied, systems combining multiple relaxation pathways remain largely unexplored. This study demonstrates that small geometric modifications lead to pronounced changes in excited‐state relaxation pathways. The combination of rational molecular design, empirical classification, and theoretical analysis provides a general strategy for controlling excited‐state dynamics. Depending on the degrees of rotational freedom, we achieved a variety of different emission properties, including the first dual‐emitting planarized and twisted intramolecular charge transfer (PLATICT) compound. These findings establish design principles for multistate fluorophores and open new perspectives for the development of responsive molecular systems and light‐driven molecular motors.