Solubility of individual light fullerenes (C₆₀ and C₇₀) in n-heptane was measured in the ranges of pressure from 0.1 up to 110 MPa and temperature from 298.3 to 358.3 K. At 0.1 MPa, the solubility diagrams of the C₆₀ – n-heptane, C₇₀ – n-heptane binary systems consist of only one branch corresponding to crystallization of mono-solvated fullerenes – C₆₀·C₇H₁₆ and C₇₀·C₇H₁₆. The compositions of the solid crystalline solvates were determined by thermogravimetric analysis. Thermodynamic description of the temperature and pressure dependences of solubility was performed using the van-der-Waals differential equation. As a result, the changes of the isothermal compressibility, molar volume, isobaric heat capacity and molar entropy in the process of the light fullerenes dissolution with formation of infinitely diluted solution were calculated.