Theoretical investigation of electrostatic solvation effects in binary solvent mixtures composed of non-polar and polar ingredients require the elaboration of advanced continuum solvent models in order to treat explicitly the non-uniformity of the dielectric medium, which is an inherent feature of such complicated systems. The present article gives a concise account of the appropriate continuum-level theory developed recently and tested on the solutions of spherical Born ions in the mixtures of benzene and dimethylsulfoxide (DMSO). Its further application for studies of the interaction of ion pairs in the same solvent mixtures with the DMSO contents varying in a wide range is reported. The results are compared with the MD simulations of the same systems which allows for the proper calibration of the parameters of the continuum solvent model. (C) 2010 Elsevier B.V. All rights reserved.