A BCNO-based long-persistent phosphor prepared by a low-temperature liquid-phase route is investigated. It shows a phosphorescence peak centered at 520 nm and its afterglow decay curve fits t(-0.93). Electron paramagnetic resonance confirms the presence of a paramagnetic center, the signal of which exhibits a synchronized decay with the afterglow intensity. We assume that the phosphorescence arises from electrons that are thermally released from nitrogen vacancies and then fall into the carbon-related defects, giving the greenish emission. The BCNO material is a competitive long-persistent phosphor because it is derived from cheap raw materials. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3082399] All rights reserved.