The long sought N-5(-) is a step from the recently synthesized aromatic pentagonal diphosphatriazolate anion (P2N3-). As accurate spectroscopic properties of N-5(-) are only known from theoretical calculations, this manuscript demonstrates the accuracy of the computed P2N3- spectra (IR, Raman, and NMR) obtained from coupled-cluster methods [CCSD or CCSD(T)] compared to experiment, eliminating any ambiguities of the prior density functional theory (DFT) results. Excited and ionized state calculations from EOM-CCSD(T) and IP-EOM-CCSD offer predictions of those additional properties. Differences between P2N3- and N-5(-) arise primarily due to the positive electron affinities of P-2, which cause very different potential energy surfaces. Published by Elsevier B.V.