Vibrationally resolved negative ion photoelectron spectra of B3N- at 355 and 266 nm are presented. Two intense bands are observed with adiabatic detachment energies (ADEs) of 2.923 +/-0.008 eV and 3.063 +/- 0.008 eV and markedly different photoelectron angular distributions. Aided by electronic structure calculations, the two bands are assigned to transitions from the linear (X) over tilde (4)Sigma(-) state of B3N- to the linear (3)Pi and (5)Sigma(-) electronically excited states of neutral B3N, with all three states having a B-N-B-B structure. Weak signal observed at lower electron binding energies is tentatively assigned to two additional linear-to-linear transitions from the low-lying electronically excited (2)Pi state of B3N- to the (1)Sigma(+) and (3)Pi states of neutral B3N. Based on these assignments the electron affinity of linear B-N-B-B is 2.098 +/- 0.035 eV. It remains uncertain if the (1)Sigma(+) state of linear B-N-B-B or the (3)A(1) state of cyclic B3N is the overall ground state. At the highest level of theory used here, CCSD(T)/aug-cc-pVTZ, the (1)Sigma(+) state is predicted to lie 0.09 eV below the (3)A(1) state.