Ten mesomeric betaines of the pyridinium azolate class have been prepared from the corresponding pyridinium azole salta. Theoretical calculations (MNDO), experimental dipole momenta (10 to 19 D),'H and I3C NMR spectra, and the X-ray structure of pyridinium benzimidazolate inner salts 3 and 17 have been used to determine the electronic and molecular structure of these compounds.
