We calculated photoelectron angular distributions From omega-(n-pyrrolyl)alkanethiol self-assembled monolayers (pyrrolyl-SAMs) for different pi molecular orbitals, pi (N) and pi (C), originating from the pyrrole group. The calculations were carried out within a single-scattering approximation of photoemission process. In the approximation, the photo-electron intensity Is caused by not only the self-scattering waves from a pyrrole group but also the single-scattering waves scattered in the vicinity of the pyrrole group, Therefore, the angular patterns involve information on the surface arrangement of the pyrrole groups as well as the character of the molecular orbitals.