Abstract: | Super‐resolution imaging of live cells over extended time periods with high temporal resolution requires high‐density labeling and extraordinary fluorophore photostability. Herein, we achieve this goal by combining the attributes of the high‐density plasma membrane probe DiI‐TCO and the photostable STED dye SiR‐Tz. These components undergo rapid tetrazine ligation within the plasma membrane to generate the HIDE probe DiI‐SiR. Using DiI‐SiR, we visualized filopodia dynamics in HeLa cells over 25 min at 0.5 s temporal resolution, and visualized dynamic contact‐mediated repulsion events in primary mouse hippocampal neurons over 9 min at 2 s temporal resolution. HIDE probes such as DiI‐SiR are non‐toxic and do not require transfection, and their apparent photostability significantly improves the ability to monitor dynamic processes in live cells at super‐resolution over biologically relevant timescales. |