The ligand-ligand interaction energies calculated by the semi-empirical dynamic volume model (the red dotted line in Figure ) are in excellent agreement with the values derived from NMR experiments (the black dotted line in Figure ). This semi-empirical model further predicts the interaction energies of a full series of binary mixed-ligand combinations without the assist of further NMR measurements 4d). As expected, the predicted interaction energy (𝐸 ) gives a linear dependence with respect to the measured dispersity: ln(𝐷) = 𝑘 𝐸 + 𝑑 (9) where 𝑘 = -0. In conclusion, we have developed a comprehensive strategy based on the "dynamic volume" concept to elucidate the cooperative interactions of organic ligands on NCs. This strategy translates the amplitude of segmental motion derived from advanced NMR measurements into the energy of ligand-ligand interaction. The energy resolution can reach a delicate level of ~10 -12 eV (i.e., the accessible frequencies of dipolar or quadrupolar interactions) for the measurement of minuscular intermolecular interactions. We show that the calculated interaction energy determines the thermodynamic properties of NC assemblies including solution dispersity and melting transition temperature. The analysis has been applied to NCs with ligands of different lengths, and can be extended empirically without direct NMR measurements. We expect the dynamic volume concept to go beyond the nanocrystal system and provide a precise and practical strategy to quantify weak interactions in many complex structures with soft and flexible components including supramolecular assemblies , polymers , biomolecular interfaces , etc.