The dissociation pathway of D-2h N-4 has been investigated at the CASSCF level of theory. A new C-2v transition state to dissociation was found and characterized on the potential energy surface. The effective barrier of dissociation from D-2h N-4 to 2N(2) is estimated to 6.5 kcal/mol from MR-AQCCNTZ//CAS(12,12)/VTZ calculations. Vertical excitation energies and oscillator strengths for the lowest 20 singlet states of D-2h N-4 have been calculated using the EOM-CCSD method. The geometry of the first excited state B-1(3u), considered as the lowest optically accessible state, has been optimized and characterized at various computational levels. This state might be useful for detection of D-2h N-4 by means of laser-induced fluorescence (LIF) spectroscopy.