The infrared spectra (650–145 cm−1) of the complexes [Zn(py)2X2] and [Zn(pyO)2X2] (py = pyridine; pyO = pyridineN-oxide; X = Cl, Br, I) are discussed. Observation of the band shifts induced by deuteration of the heterocyclic rings and by halogen substitution enables unambiguous assignments of νZn-X and νZn-N or νZn-O. In each spectrum, two νZn-X and two νZn-N or νZn-O bands are found. The effect on the spectra of varying the halogen in the pyridineN-oxide complexes suggests that the compounds [Zn(pyO)2X2] (X = Cl, Br) are grossly distorted from tetrahedral symmetry as revealed by preliminary structural studies.