For the first time we report novel BiOCl/Bi2O3 photocatailyst functional under visible light irradiation. Even though both the individual BiOCl and Bi2O3 show very low photocatalytic efficiency under visible light irradiation, their heterojunctions; provide unexpectedly high efficiency in decomposing organic compounds. Furthermore, the BiOCl/Bi2O3 can induce complete mineralization without formation of intermediate species by utilizing the holes generated in the VB of BiOCl. Compared to the Degussa P25, it demonstrates 5.7 times of efficiency in evolving CO2 from gaseous 2-propanol (IP), and 10.5 times of efficiency in removing aqueous 1,4-terephthalic acid (TA) under visible light (lambda >= 420 nm) irradiation. In this BiCCl/Bi2O3 system the BiOCl seems to work as main photocatalyst, while the role of Bi2O3 is a sensitizer absorbing visible light. The photocatalytic mechanism has been proposed based on the relative band position of these two semiconductors. (C) 2009 Elsevier Inc. All rights reserved.