The suitability of N-ethylpyridinium bromide as a potential electrolyte additive for zinc electrodeposition in aqueous solution has been investigated by a combination of cyclic voltammetry, bulk electrolysis, scanning electron microscopy, synthesis and NMR spectroscopy. The current magnitudes of the Zn/Zn(II) redox reaction observed at the electrode decreased dramatically after a single deposition/stripping cycle in the presence of N-ethylpyridinium bromide at switching potentials more negative than -1.30 V vs Ag/AgCl. This is attributed to the reduction of the N-ethylpyridinium cation to form a pyridyl radical that subsequently and rapidly dimerizes. The proposed dimer was synthesized and shown to have a low solubility in aqueous solutions, consistent with a passivation of the electrode surface by precipitation and inhibition of redox behavior. Based on this understanding for the pyridinium cation reduction, alternative pyridinium-based additives have been examined in order to determine their influence on zinc electrodeposition. (C) 2019 The Electrochemical Society.