Autofluorescence-free in vivo imaging using a cyclometalated iridium complex with afterglow luminescence

We present an iridium complex (SO-IrD) with afterglow luminescence by photochemical reaction driven by singlet oxygen. The SO-IrD molecule shows an afterglow time of up to 0.78 seconds at room temperature. Based on the time-resolved afterglow properties, the SO-IrD is further applied for autofluorescence-free bioimaging in vivo.