pi stacking and water-solubility of methyl blue (MB) are expected to facilitate the hydrazine mediated reduction of graphene oxide (GO) in aqueous environment. Our newly obtained MB-functionalized reduced graphene oxide (MB-rGO) exhibited excellent solubility and stability in water. The results showed that the MB molecules stacked non-covalently onto the basal plane of rGO while the sulfo groups of MB prevented the rGO from aggregation. In addition, the better electrical conductivity of MB-rGO than that of GO was analyzed. This novel conductive MB-rGO should have promising applications in diverse nanotechnological areas, such as electronic and optoelectronic devices, photovoltaics, sensors, and microfabrication. (C) 2011 Published by Elsevier Ltd.