The reaction between the pyrazolo[1,5-a]pyridine-2,3-dicarboxylic acid 1 and SOCl₂ has been studied within the Density Functional Theory (DFT) B3LYP/6-31G(d,p) computational level. Examination of the conceptual DFT reactivity indices permit the elucidation of the reactivity, and the regio- and chemoselectivity experimentally observed. The possible regioselective channels and chemoselective channels were explored and characterized. Analysis of the energies associated with the different reaction pathways shows that this reaction is completely chemioselective and regioselective, in conformity with the experimental results.