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Elucidating structural roles in photoinduced charge transfer is indispensable, as nuclear rearrangements are simultaneously usually involved in the dynamics. However, it is hard to evaluate whether the structural changes occur or not by using conventional time‐resolved electronic spectroscopy. Here, time‐resolved impulsive stimulated Raman spectroscopy is applied to record the evolution of vibrational snapshots during charge‐separation dynamics of donor–acceptor–donor‐type quadrupolar perylene bisimide in real time. Drastic frequency shifts were observed for several Raman bands with their population kinetics, thus symmetry‐breaking charge separation accompanies significant structural changes, as supported by (TD)‐DFT calculations. A comparison between time‐resolved Raman spectra of the neutral S1 state and the radical anion species shows that the spectral signatures, especially in high‐frequency regions, provide important clues to bond length alternation patterns in the PBI core. [ABSTRACT FROM AUTHOR]

Time‐resolved impulsive stimulated Raman spectroscopy, which is an ultrafast time‐domain Raman technique, facilitates capturing vibrational snapshots of excited‐state molecules with high sensitivity and time resolution. By using this technique, D. Kim and co‐workers demonstrate in their Research Article on page 8571 that structural symmetry breaking is an important prerequisite for a charge separation reaction in a donor–acceptor–donor perylene bisimide. [ABSTRACT FROM AUTHOR]

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