Ionic liquids (ILs) have become advantageous solvents for the dissolution and homogeneous processing of cellulose in recent years. However, despite significant efforts, only a few ILs are known for their capability to efficiently dissolve cellulose. In order to overcome this limitation, we screened a wide range of potentially suitable ILs. From our studies, some remarkable results were obtained, for example, an odd-even effect was found for different alkyl side-chain lengths of the imidazolium chlorides which could not be observed for the bromides. Furthermore, 1-ethyl-3-methylimidazolium diethyl phosphate was found to be best suitable for the dissolution of cellulose; dissolution under microwave irradiation resulted in almost no color change. No degradation of cellulose could be observed. In addition, 1-ethyl-3- methylimidazolium diethyl phosphate has a low melting point which makes the viscosity of the cellulose solution lower and, thus, easier to handle. © 2009 The Royal Society of Chemistry.