The infrared spectrum of the anion dicyano[(dithionitrito-S) amido]nickelate(II), [Ni(CN)2(S2N2H)]−has been measured from 4000 to 200 cm−1. The absorption bands have been assigned by comparison to those of Ni(CN)42and Ni(S2N2H)2. Normal coordinate analysis on the Csplanar anion [Ni(CN)2(S2N2H)]−has been carried out using molecular parameters taken from X-ray data. Band assignments for the observed frequencies in this complex are in good agreement and show an average error of less than one half of one percent. In order to obtain good agreement between calculated and observed frequencies, it was necessary to modify the Urey-Bradley force field by adding selected interaction force constants. Its electronic spectrum is also discussed.