Liquid-phase exfoliation is a mass-scalable approach for the production of graphene and other 2-dimensional crystals.However, this method is not efficient with common solvents such as water.In this work we show a simple and efficient method to produce high quality graphene in water, based on the use of organic dyes such as pyrene derivatives.Stable suspensions of graphene containing ~30% single-layers in suspension, with average lateral size of 200-400 nm, have been produced by using water only as solvent.