In this work, we successfully synthesized rhombic dodecahedral Cu2O nanocrystals with a size of 300 – 400 nm using a facile hydrothermal method. The as-prepared photocatalyst with narrow bandgap is activated using low power visible LED light sources and shows high efficiency in degrading aromatic organic compounds including toluene and chlorobenzene. The OH substitution leads to oxidation/ionization potential drops while the nature of the p-type Cu2O contributes to an effective single electron transfer reaction.