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In the present study, the role of α-relaxation toward isothermal crystallization of amorphous celecoxib was studied using dielectric spectroscopy (DES). The dielectric response of the α-relaxation was measured as a function of frequency (10^–1 to 10⁶ Hz), isothermally at every 4 K interval in the range of 303.15 to 443.15 K. The dielectric loss spectrum at each temperature was analyzed using the Havriliak Negami (HN) equation to extract the characteristic relaxation time, τ_HN. Two Vogel–Fulcher–Tammann (VFT) functions were required for representing the temperature dependence of τ_HN across the temperature range of study. The VFT fit parameters obtained from the two regions varied drastically pointing toward the underlying differences in the dynamics of relaxation above and below the crossover. Later, in situ isothermal crystallization experiments were performed at 363.15, 368.15, 373.15, and 378.15 K. The …