Neutral NCCCCCN may be prepared in a collision cell of a VG ZAB 2HF mass spectrometer by charge stripping of (NCCCCCN)(center dot-), formed in the ion source by the process NCCCCH(OEt)(CN) + HO- -> H2O + NCCCC-(OEt)(CN) -> (NCCCCCN)(center dot-) + EtO center dot. A comparison of the neutralization/reionization (-NR+) and charge reversal (-CR+) spectra of (NCCCCCN)(center dot-) indicate that some neutrals NCCCCCN are energized and rearrange to ail isomer which decomposes by loss of carbon. An ab initio study at the CCSD(T)/cc-pVTZ//B3LYP/6-311+G(3df) level of theory indicates that (i) triplet NCCCCCN is the ground state with a T/S energy gap of -14.9 kcal mol(-1); (ii) the structures of triplet and singlet NCCCCCN need to be described by molecular obital theory, and a simple valence bond approach cannot be used for this system; and (iii) there are several possible routes by which ail energized neutral may lose carbon, but the major route involves the triplet nitrile to isonitrile rearrangement NCCCCCN -> CNCCCCN -> NCCCCN + C.