Using translational diffusion, viscosimetry, and Kerr electrooptical techniques, it was found that the properties of fullerene C₆₀ in the N-methylpyrrolidone and N-methylmorpholine media are determined by the duration of storage of the solutions. It was shown that, in these solvents, the fullerene passes into solution in the form of individual molecules, forming fullerene-solvent aggregates. The physical properties of these aggregates (the degree of asymmetry and optical anisotropy) were found to vary with time.