The unimolecular dissociation of the pyrene radical cation, C16H10+center dot, has been explored using a combination of computational techniques and experimental approaches, such as multiple photon absorption in the cold ion trap Piege a Ions pour la Recherche et l'Etude de Nouvelles Especes Astrochimiques (PIRENEA) and imaging photoelectron photoion coincidence spectrometry (iPEPICO). In total, 22 reactions, involving the fragmentation cascade (H, C2H2, and C4H2 loss) from the pyrene radical cation down to the C-14(+center dot) fragment ion, have been studied using PIRENEA. Branching ratios have been measured for reactions from C16H10+center dot, C16H8+center dot, and C16H5+. Density functional theory calculations of the fragmentation pathways observed experimentally and postulated theoretically lead to 17 unique structures. One important prediction is the opening of the pyrene ring system starting from the C16H4+center dot radical. In the iPEPICO experiments, only two reactions could be studied, namely, R1 C16H10+center dot -> C16H9+ + H (m/z = 201) and R2 C16H9+ -> C16H8+center dot + H (m/z = 200). The activation energies for these reactions were determined to be 5.4 +/- 1.2 and 3.3 +/- 1.1 eV, respectively.