Activatable BODIPY-chromene NIR-II probes with small spectral crosstalk enable high-contrast in vivo bioimaging.

Herein, we design a novel "crossbreeding" dye (BC-OH) within the second near-infrared (NIR-II) window based on BODIPY and chromene chromophores. BC-OH can serve as a platform to construct activatable NIR-II probes with small spectral crosstalk, thereby making a breakthrough in imaging HO fluctuation in an APAP-induced liver injury model with high signal-to-background ratio.