The enhancement of nonlinear optical phenomena in fullerene solutions is treated in terms of the model of amplification of local electric field due to resonance excitation of clusters, which are extended chargetransfer complexes. Excitation light is transformed in the clusters into local charge-transfer excitons, inducing polarization of the medium sufficient for amplification of the local electric field of incident and exiting light. The intensity of the observed linear optical phenomena has been directly correlated with the magnitude of the nonlinear characteristics of the medium on one hand and the efficiency of clustering on the other hand. The gain coefficients have been determined. Experimental and computational testing procedures that make it possible to determine suitability of the fullerene-doped matrix for nonlinear-optics applications are proposed. © Pleiades Publishing, Ltd., 2009.