Crucial Breakthrough of BODIPY‐Based NIR‐II Fluorescent Emitters for Advanced Biomedical Theranostics

Abstract Fluorescence imaging in the second near‐infrared window (NIR‐II, 1000–1700 nm) has aroused immense attention for biomedical applications, offering exceptional advantages such as ultra‐low photon scattering and increased tissue penetration. Among the NIR‐II‐emitted organic dyes, Boron dipyrromethene (BODIPY), has emerged as a noteworthy candidate. BODIPY, distinguished by its controllable molecular structure and optical properties, outstanding fluorescence quantum yields, high molar absorption coefficients, and remarkable chemical stability, has undergone comprehensive investigation and extensive exploration within the realm of biological theranostics. This work aims to provide a comprehensive summary of the advancements in the development and design strategies of NIR‐II BODIPY fluorophores tailored for advanced biological phototheranostics. Initially, the work elucidates several representative and controllable strategies, concluding the electron‐programming strategy, extension of the conjugated backbone, J‐aggregation strategy, and strategic establishment of activatable fluorophores, which enhance the NIR‐II fluorescence of BODIPY skeletons. Subsequently, developments in NIR‐II fluorescent BODIPY‐based nanoplatforms for biological applications are intricately elaborated. In conclusion, this work outlines future efforts and directions for refining NIR‐II BODIPY to meet evolving clinical demands. It is anticipated that this contribution may provide a feasible reference for the strategic design of organic NIR‐II fluorophores, thereby advancing their potential in future clinical practices.