Development of a group contribution method for determination of viscosity of ionic liquids at atmospheric pressure

► A data set consisting of 1672 viscosity values and comprising 443 ILs was collated from the literature.► A reliable group contribution method has been developed using this dataset.► The method employs a total of 46 sub-structures in addition to the temperature to predict the viscosity of ILs.► Twenty four sub-structures related to anions, and 22 sub-structures related cations were implemented.► The model produces very encouraging results.