Visible light irradiation of an O-2-saturated acetonitrile (MeCN) solution containing 9-mesityl-10-methylacridinium ion (Acr(+)-Mes) and MeCN-extracted coal tar results in formation of hydrogen peroxide (H2O2). Anthracene and other aromatic hydrocarbons contained in coal tar act as hydrogen sources in the photocatalytic reduction Of O-2 to produce H2O2. The photocatalytic formation of H2O2 is initiated by photoexcitation of Acr(+)-Mes, which results in formation of the electron-transfer state: Acr(center dot)-Mes(center dot+), followed by electron-transfer from coal tar to the Mes(center dot+) moiety and electron-transfer from the Acr(center dot) moiety to O-2. (C) 2007 Elsevier B.V. All rights reserved.