Fukui Function reveals potential sites of reaction. We used computational methods to enumerate potential reaction sites. Specifically, we identified atoms with higher probability of either gaining or losing an electron within the most stable isomeric forms of 4-BrPyCN and 4-IPyCN (including structural isomers and stereoisomers); these conformations were generated using Auto3D ANI Neural Network Potentials . Scheme 2 shows the highest condensed-to-atom Fukui Indices (fA) of I obtained using finite differences method . The population analysis of cations and anions was performed at the same equilibrium geometry as the initial neutral molecule to avoid system relaxation. The highest fA indicated the most reactive position towards an incoming electrophile or nucleophile (Table ). As illustrated in Scheme 2, the most probable nucleophilic site within I was computed to be the carbon alpha to the pyrazolyl nitrogen and terminal nitrile (fA -(C) = 0.55). Thus, after the first step of the reaction, I yielded the same products irrespective of the halogen substituent at the C4 site within the pyrazolyl heterocycle i.e., III-Br and III-I (R1, Scheme 2). This was further corroborated by the similar relative free energy values calculated for the respective transition states (II-Br and II-I in Scheme 2) and the products (III-Br and III-I in Scheme 2).