The ionic liquid choline arginate [Ch][Arg] is more effective for coal pretreatment than other choline based amino acid ILs, but the underlying mechanism is unclear. Calculations to show that for gas phase R-OH•••[Arg][Ch], [Arg] adopts a closed (ring) conformation.The cation charge group associates closely with the anion charge centre, and the ring structure places the cation charge group is in close proximity to the hydrogen bond formed by the HBD and anion guanidine sp2 nitrogen. This leads to polarisation of the H-bond: the charge on partial negative atoms becomes more negative, and the partial positive charge of the proton increases, leading to strong H-bonds. In this work we will determine whether this gas phase conformation is present in pure liquid phase [Arg][Ch], in the presence of a model coal/biomass H-bond donor (guaiacol), and the effect of added water.