Fluorescent probes are powerful tools for the investigations of reactive oxygen species (ROS) in living organisms by visualization and imaging. As one of the most important of the natural reactive oxygen species (ROS), hypochlorous acid (HCIO) plays a crucial role in various physiological and pathological processes. We report herein a new redox-switchable NMOF of UiO-68-ol via a direct ligand modification approach. The obtained UiO-68-ol NPs, which contains organic-based molecular redox switches, exhibit excellent photophysical properties for biological application and can be highly sensitive and selective fluorescent probes to detect HCIO species in living cells.