The temperature dependence of toluene H-2 and C-13 NMR spin-lattice (T-1) relaxation times has been analyzed assuming molecular isotropic rotational diffusion and a Cole-Davidson distribution of correlation times. Results indicate that-accurate representations of the T-1(T) data can be achieved if data on both sides of the T-1 minimum are obtained. Resultant regression parameters can be equated to solvent free-volume parameters employed in the Vrentas-Duda models for diffusion in polymer/solvent systems and agree well with values extracted from viscosity data. Predictions of diffusion coefficients as a function of temperature and concentration using the solvent parameters determined from NMR relaxation or viscosity studies are identical.