We present an optochemical O2 scavenging system that enables precise spatiotemporal control of the level of hypoxia in living cells simply by adjusting the light intensity in the illuminated region. The system employs rhodamine containing a selenium or tellurium atom as an optochemical oxygen scavenger that rapidly consumes O2 by photochemical reaction with glutathione as a coreductant upon visible light irradiation (560–590 nm) and has a rapid response time, within a few minutes. The glutathione‐consuming quantum yields of the system were calculated as about 5 %. The spatiotemporal O2 consuming in cultured cells was visualized with a hypoxia‐responsive fluorescence probe, MAR. Phosphorescence lifetime imaging was applied to confirmed that different light intensities could generate different levels of hypoxia. To illustrate the potential utility of this system for hypoxia research, we show that it can spatiotemporally control calcium ion (Ca2+) influx into HEK293T cells expressing the hypoxia‐responsive Ca2+ channel TRPA1.

We present an optochemical O2 scavenging system that enables precise spatiotemporal control of the level of hypoxia in living cells simply by adjusting the light intensity in the illuminated region. The system employs rhodamine containing a selenium or tellurium atom as an optochemical oxygen scavenger that rapidly consumes O2 by photochemical reaction with glutathione as a coreductant upon visible light irradiation (560–590 nm) and has a rapid response time, within a few minutes. The glutathione‐consuming quantum yields of the system were calculated as about 5 %. The spatiotemporal O2 consuming in cultured cells was visualized with a hypoxia‐responsive fluorescence probe, MAR. Phosphorescence lifetime imaging was applied to confirmed that different light intensities could generate different levels of hypoxia. To illustrate the potential utility of this system for hypoxia research, we show that it can spatiotemporally control calcium ion (Ca2+) influx into HEK293T cells expressing the hypoxia‐responsive Ca2+ channel TRPA1.