The mole fraction solubility of bioactive iminodibenzyl in aqueous co-solvent mixtures of ethanol, ethylene glycol (EG), dimethyl sulfoxide (DMSO) and isopropanol was examined by the saturation shake-flask method over the temperature range from 283.15 K to 328.15 K at pressure of 101.2 kPa. The experimental solubility increased with increasing temperature at a given co-solvent composition and decreased with the increasing mass fraction of water in each binary system. The maximum solubility was found in pure co-solvent. Given the same temperature and mass fraction of the co-solvent, the solubility of iminodibenzyl was greater in (DMSO + water) than in the other three co-solvent systems. The solid crystal examples of iminodibenzyl was tested by X-ray power diffraction showing no polymorphic transformation, solvate formation or crystal transition during entire experiments. The Jouyban-Acree model was employed to correlate the measured solubility. The calculated data were in alignment to measured values and RAD and RMSD data were no more than 3.08% and 10.37 x 10(-4), respectively. Furthermore, quantitative values for the local mole fraction of ethanol (EG, DMSO or isopropanol) and water around the iminodibenzyl were acquired by using the Inverse Kirkwood-Buff integrals method. The preferential solvation parameters for ethanol, EG, DMSO or isopropanol were positive in the four co-solvent mixtures in intermediate and co-solvent-rich compositions, which indicated that iminodibenzyl was preferentially solvated by the co-solvent. iminodibenzyl could act mainly as a Lewis acid interacting with proton-acceptor functional groups of the co-solvents. (C) 2018 Elsevier Ltd.