CO2 solubility in ionic liquids (ILs) over wide temperature and pressure ranges of (283.15-373.35 K) and (99.8-85800.0 kPa), respectively, has been predicted using three models; a group method of data handling correlation (model I), a radial basis function network (model II), and an empirical relation (model III). The Nelder-Mead simplex and Levenberg-Marquardt algorithms were used to find the constants of the suggested functionality relations for models I and III, respectively. Model I with R-2, RMSE and AARD% of 0.9650, 4.2727 and 8.46, respectively; model II with R-2, RMSE and AARD% of 0.9942, 1.7172, and 4.23, respectively and model III with R-2, RMSE and AARD% of 0.9886, 2.4248 and 4.25, respectively, were highly accurate in the prediction of experimental values. All the models proposed are vigorous and possess satisfactory error trends based on a comprehensive statistical assessment. To confirm the validity of the database, the dataset was subjected to a statistical outlier diagnostic test. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.