Abstract Thermochemical parameters, in terms of standard enthalpies of formation, standard entropies and Gibbs free energies of formation and heat capacities are calculated herein for all chlorinated isomers of aniline. Calculated values of standard enthalpies of formation are in agreement with the available experimental values. Calculated values of solvation energies indicate that the interaction of chlorinated aniline with water molecules decreases with the degree of chlorination. Trends in angles and barriers of inversion indicate that the pyramidalisation in chlorinated aniline decreases with the degree of chlorination. The most stable isomer in each homologue group is highlighted. Interaction of ortho chlorine atoms with the electron donating group of amine affords ortho-substituted isomers slight stability over other isomers.