Using photochemistry to understand and control the production of reactive oxygen species in biological environments

•Reactive oxygen species.•Photoinduced electron transfer fluorescent probes.•Förster resonance energy transfer fluorescent probes.•Photosensitizer.•Nanoparticles as singlet oxygen generator.

Reactive oxygen species (ROS) originating from the metabolism of molecular oxygen are a double-edge sword. Their involvement in various diseases is well documented, while they also serve essential signaling functions. In order to shed light on their biochemical role, chemical tools have been designed for ROS detection and production. This featured article describes and illustrates different photochemical processes, which have been exploited to engineer new probes for the detection and the site-specific production of ROS.