4,5-Dimethylthio-4'-[2-(9-anthryloxy)ethylthio]tetrathiafulvalene has been designed and synthesized as a highly selective and sensitive chemiluminescence (CL) probe for singlet oxygen (O-1(2)). The design strategy for the probe is directed by the idea of photoinduced electron-transfer process and carried out through the incorporation of electron-rich tetrathiafulvalene unit into a reactive luminophore of anthracene specific for O-1(2). Upon reaction with reactive oxygen species (ROS), such as hydrogen peroxide, hypochlorite, superoxide, hydroxyl radical, or O-1(2), the probe exhibits both strong CL response to and high selectivity for O-1(2) only, rather than the other ROS. This remarkable CL property permits O-1(2) to be distinguished easily from the other ROS and makes the probe possible to be used widely for O-1(2) detection in many chemical and biological systems and even in light water (H2O) environments. This applicability has been demonstrated by monitoring the O-1(2) generation in a metal-catalyzed decomposition system of tert-butyl hydroperoxide. Moreover, the CL reaction mechanism of the present system is also discussed, clearly confirming that the introduction of electron-rich tetrathiafulvalene into the 9-position of anthracene can greatly activate its reactivity toward O-1(2).