Where q i is the 𝜋-electron density of atom i, r ij is the internuclear distance between atom i and j, and A and B are constants. To this end, another salient factor other than the π-donating capabilities of the substituents attached to boron in B NMR, would be the 'electronic cloud' of the substituents attached to boron i.e. the availability of lone pairs above and below of the plane of the π-bond. As exemplified by the last equation above (Eq. III), atoms j with lone pairs orthogonal to the plane of the covalent bond would have a significant impact on the chemical shift by virtue of a large 𝑞 𝑗 and small 𝑟 𝑖𝑗 (Table ). Analysis of the 1 H, 13 C and 11 B NMR data above (Table ), on looking more closely, reveals that whilst the boron in 2-FPBA has a much greater trivalent character, less shielded and non-aromatic relative to that of quadrivalent diazaborines which should be more shielded, they all absorb at about the same field in their B NMR; on the other hand, the proton of the formyl group in 2-FPBA, resonates at a much lower field than that from γ-CH of the benzofused-imadazo ring in their 1 H NMR by virtue of greater shielding that the γ-CH moieties of benzofused-imadazo rings experience, which is in marked contrast to that observed for 11 B NMR. The same is also true for 13 C NMR data, the γ-CH and γ-CMe of the imidazo rings are significantly upshifted compared to the non-ring carbon of the formyl group in 2-FPBA (Table ). Intriguingly, the solvation effects of methanol-d 4 on benzodiazaborine 4 (vide infra) relative to that of acetonitrile-d 3 for its closely related benzodiazaborine 5 has clearly been echoed by both the upshifted and downshifted signals from boron and γ-CH of benzodiazaborine 4 in its B and 13 C NMR spectra, respectively. The 11 B chemical shifts from the boronate esters, in comparison with those from the diazaborines, exhibit a whopping three-fold upfield shift in their spectra, in spite of the fact that both species are quadrivalent, and potentially negatively charged.