The presented work deals with the influence of the mesoionic additives on conductivity of proton-conducting polymer gels. Different characteristics of gel electrolytes were examined as a function of solvent, type, and concentration of mesoionic compound and amount of acid. We found that the additives, such as thia- or tetrazoles, improve the conductivity of the systems, based on NN-dimethylformamide, while the properties of the NN-dimethylacetamide- and N-methylpyrrolidone-based gels were practically unaffected. Intermolecular interactions between different electrolyte components were investigated by PFG NMR and vibrational spectroscopy. Spectroscopic data show that in the present systems mesoionic compounds are preferably protonated by acid in competition with the solvent.