A laboratory experiment in which [superscript 1]H NMR and UV-vis spectroscopies are applied to probe the temperature dependence of a monomer-dimer equilibrium involving a cyclopentadienone derivative is described and discussed. Details of the data analysis for extraction of equilibrium constants from the raw experimental data from both techniques are provided, leading to the determination of thermodynamic parameters ([delta][subscript r]H° and [delta][subscript r]S°) via van't Hoff analysis. Fully analyzed datasets are provided in the Supporting Information to aid adaptation of the experiment or its use as a data analysis activity.