Deep-Red and Near-Infrared Xanthene Dyes for Rapid Live Cell Imaging

In this work, two xanthene dyes (<b>H-hNR</b> and <b>TF-hNR</b>) have been synthesized by a convenient and efficient method. These two dyes exhibited deep-red and near-infrared emissions, high fluorescence quantum yields, and good photostability. Their structure–optical properties were investigated by X-ray crystal structure analysis and density functional theory calculations. Live cell imaging data revealed that <b>H-hNR</b> and <b>TF-hNR</b> could rapidly stain both A549 and HeLa cells with low concentrations. The excellent photophysical and imaging properties render them as promising candidates for use in live cell imaging.