A conceptual DFT study of the dissociation of anionic and neutral phosphonate dimers has been carried out. In addition, the dianion complexes have been studied in the presence of two solvents, water and tetrahydrofuran. The dissociation of the dianion complexes in the gas phase and in solution present a maximum along the reaction coordinate that is not present in the neutral-neutral and anion-neutral complexes. The principal chemical descriptors (chemical potential, reaction electronic flux, hardness, and global electrophilicity index) do not show changes in their trends along the dissociation profiles even when there is an energy maximum in the case of the anion-anion complexes.