Tailored Asymmetric Electron Structure Triggered Efficient NIR‐II Dual Emission of Carbon Dot Nanogel for Precise Bioimaging and Efficient Anti‐Angiogenesis

ABSTRACT Nano‐fluorophores operating in the second near infrared II (NIR‐II) window show high spatiotemporal precision and efficiency and hold significant potential in biomedical engineering due to reduced light scattering and tissue autofluorescence. However, the emission wavelengths and fluorescence quantum yields (QY) of such fluoroprobes are far from desired values due to limited regulation of electronic structures. Here, a tailored asymmetric electron structure was achieved through B, N co‐doping in carbon dot nanogels, inducing distinct NIR‐II dual‐emission. Ultranarrow emission peaks with full width at half maximum of 5 and 21 nm at 1233 and 1350 nm, respectively, were observed after excitation at 1200 nm. The absolute QYs reached extremely high values of 7.98% and 6.66% under 808 and 1200 nm excitation, respectively. Density functional theory calculations indicate the N‐B‐N configuration could lower the HOMO‐LUMO gap to 1.48 eV, facilitate the electron transition between two N atoms, and trigger intramolecular charge transfer over the graphitic plane. Thus, non‐invasive real‐time vascular imaging could be achieved. Furthermore, the nanogels exhibited significant angiogenesis inhibition, as demonstrated in choroidal neovascularization models. This study demonstrates that the tailored B, N co‐doping provides a new approach to achieving precise bioimaging and anti‐angiogenesis nanomaterials.