Special attention has been paid to the organic afterglow materials (OAM) for their fascinating properties. However, poor stability at air and complicated structure design hinder the development of OAM. Herein, sol-gel, a facile and simple technique, is employed to synthesize a series of organic/inorganic hybrid nanocomposites (N1/SiO₂, N2/SiO₂, and N3/SiO₂) by covalently linking three common aryl imides with crosslinked silica skeleton. These nanomaterials show excitation wavelength-dependent and colorful (yellow, red and green) afterglow of organic imides with long lifetime up to 1.1 s at air. Interestingly, the ultralong phosphorescence is ultrastable under various conditions: water, high temperature, UV irradiation and in vivo, due to the protection of inorganic silica. In particularly, heating to 500 ^oC does not quench the afterglow of organic luminophore in nanocomposites, but forms new ultralong phosphorescence originated from space-conjugation of silica and carbonyl. The afterglow nanomaterials display huge advantages in the applications of advanced anti-counterfeiting and bioimaging.

Aggregation-induced emission luminogens (AIEgens) are fluorescent agents that are ideal for bioimaging and have been widely used for organelle targeting, cellular mapping, and tracing. Owing to their promising characteristics, AIEgen-based nanoparticles have recently been used for the stimulated emission depletion (STED) super-resolution imaging of fixed cells. In the present study, and for the first time, we used an AIEgen for dynamic STED nanoscopic imaging of a specific organelle in live cancer cells. TPA-T-CyP is a synthetic red & NIR-emitting luminogen with AIE features that can spontaneously and specifically aggregate on mitochondria without the need for encapsulation or surface modification. The STED efficiency of aggregated TPA-T-CyP can reach more than 80%, and super-resolution imaging of TPA-T-CyP-stained mitochondria in live HeLa cells is possible, with a lateral spatial resolution of 74 nm. We found that TPA-T-CyP enabled the dynamic visualization of mitochondria, and the motion, fusion, and fission of mitochondria were clearly observable on a super-resolution scale. AIEgen-based super-resolution organelle visualization has great potential for many basic biomedical studies.