Facile Access to Far‐Red Fluorescent Probes with Through‐Space Charge‐Transfer Effects for In Vivo Two‐Photon Microscopy of the Mouse Cerebrovascular System

Much effort has been devoted to the generation of fluorescent probes by synthetic approaches. In this study, we developed a facile strategy to construct far‐red fluorescent probes based on through‐space charge transfer within complexes of acceptors and donors and their “twist+twist” interactions. Owing to their rare two‐photon excitation property, the complexes could be used for in vivo imaging of the mouse cerebrovascular system. Complexes formed between aggregation‐induced emission (AIE) acceptors and arylamine donors showed through‐space charge transfer as well as a “twist+twist” interaction between the acceptor and the donor. Owing to these properties, the complexes served as far‐red fluorescent nanoprobes with two‐photon excitation. The probe was applied to in vivo imaging of the mouse cerebrovascular system.