Three different aniline derivatives, namely m-and p-aminobenzoic acids and m-amino benzenesulfonic acid, were sequestered in between layers of a borate-based coordination polymer, based on lead(II) tetrakis(imidazolyl) borate. The aniline derivatives pre-organized in the interlayer spacing of the coordination polymer, and the reactivity of these pre-organized anionic monomers in the crystalline state was studied. We found that thermally activated reactivity under ambient atmospheric oxygen promotes what appears to be polymerization, and that the most reactive species is m-aminobenzenesulfonic acid monomer due to its increased mobility within the layers of the polymer.