The photodetachment spectrum of the pyrrolide anion, C 4H 4N −, has been measured recently [A.J. Gianola, T. Ichino, R.L. Hoenigman, S. Kato, V.M. Bierbaum, W.C. Lineberger, J. Phys. Chem. A 108 (2004), 10326]. The band associated with the 1 2 A 2 ground state of the pyrrolyl radical, C 4H 4N, can be identified in the spectrum by its resolved vibrational progression. In contrast, the second band, belonging to the 1 2 B 1 first excited state of pyrrolyl, is very weak, broad, and unresolved, which suggests the presence of strong vibronic interaction effects. We have performed a theoretical study of the spectrum in the framework of the linear vibronic coupling model, using ab initio calculated parameters. It is shown that a 1 2 B 1–1 2 A 2 conical intersection is responsible for the unresolved part of the spectrum. The potential-energy surfaces of the 1 2 A 2 and 1 2 B 1 states of pyrrolyl as a function of the a 1 and b 2 ground state normal coordinates of pyrrolide have been computed with the MRCI/aug-cc-pVDZ method. Only the b 2 modes can couple the involved electronic states in first order. Five totally symmetric modes ( a 1 symmetry) and four modes of b 2 symmetry have been identified as the vibronically most active tuning and coupling vibrations, respectively. Model Hamiltonians for the description of the dynamics in the coupled vibronic manifold of the 1 2 A 2 and 1 2 B 1 states, including different subsets of these nine modes, have been constructed. The simulated spectra predict a 1 2 A 2 band with sharp peaks and a very diffuse 1 2 B 1 band stretching from 2.6 to 3.3 eV with a maximum close to 3.0 eV. The calculated spectra are in good agreement with experiment. Reasons for the unexpectedly low intensity of the 1 2 B 1 band such as an extremely short lifetime of 1 2 B 1 vibronic levels or very different photodetachment cross sections for the 1 2 A 2 and 1 2 B 1 states are discussed.