1, 2, 4, 5-Tetramesitoylbenzene was synthesized and reduced with alkali metals as well as electrolytically. EPR spectra of the resulting radical-ion pairs are reported and discussed. The electron-spin densities obtained from temperature coefficient and marked solvent dependency. These effects are compared with the ones observed in the corresponding radical-ion pairs of o-dimesitoylbenzene for which some new data are also reported.