Mapping Intracellular Polarity Distribution Using an Indoline‐Based Fluorescent Probe

The intracellular microenvironmental properties are important parameters for understanding cellular health status. Herein, we report a polarity-sensitive indoline-based fluorescent probe (PPOH) for determining intracellular micropolarity. A quantitative estimate of the local polarity was obtained through extensive spectroscopic investigations. The fluorescence lifetime follows a linear relationship with solvent polarity. This property of PPOH enabled us to map the heterogeneous subcellular environment using fluorescence lifetime imaging microscopy.