Lastly, we applied the fluorogenic nanoaggregate for bioorthogonal fluorogenic imaging in living cells. First, MBTPA-Tz was added to cells, and confocal laser microscopy was used to observe the emission signals inside the cells. As expected, no emission was observed even after a 30 min incubation. After washing the cells thoroughly, BCN-OH was added and incubated for 30 min, resulting in the observation of turn-on emission inside the cell without the washing procedure (Figure , Supporting Information). This result confirms that the iEDDA reaction between MBTPA-Tz and BCN-OH can bioorthogonaly take place in congested living systems.