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Understanding phase transitions of fluids confined within nanopores is important for a wide variety of technological applications. It is well known that fluids confined in nanopores typically demonstrate freezing-point depressions, ΔT_f, described by the Gibbs–Thomson (GT) equation. Herein, we highlight and correct several thermodynamic inconsistencies in the conventional use of the GT equation, including the fact that the enthalpy of melting, ΔH_m, and the solid–liquid surface energy, γ_SL, are functions of pore diameter, complicating their prediction. We propose a theoretical analysis that employs the Turnbull coefficient, originally derived from metal nucleation theory, and show its consistency as a more reliable quantity for the prediction of ΔT_f. This analysis provides a straightforward method to estimate ΔT_f of nanoconfined organic fluids. As an example, we apply this technique to ibuprofen, an active pharmaceutical …