The aqueous solutions of mixtures (T = 25°C) of paramagnetic Gd@C82(OH) x and diamagnetic C82(OH) x fullerenols, where x ∼ 30, are studied via small-angle polarized-neutron scattering under the conditions of transition from diluted to concentrated systems whose solubility threshold is close to that of fullerenols. When the induction B of an external field varies from 0.001 to 1.0 T, the molecular correlation radius of solutions is R C ∼ 15–20 nm and the aggregation number reaches ∼5 × 104 with increasing fullerenol content (C = 0.04−2.0 wt %). Such changes are coupled with both paramagnetic Gd@C82(OH) x molecules and interactions between the induced diamagnetic moments of fullerenols introduced into aggregates.