New experimental measurements are presented for the oxidation of norbornadiene (NBD) to understand this high-energy–density additive chemistry. Experiments for a stoichiometric NBD/O2 mixture in 99.25% He/Ar were carried out in a shock tube for temperatures ranging from 1380 to 1707 K near atmospheric pressure. Two diagnostics were used in this study: CH* chemiluminescence emission and CO laser absorption spectroscopy. While excited radicals are key species produced in combustion processes and historically have received a lot of attention, novel advancements now combine chemiluminescence with laser absorption techniques during shock-tube measurements. A new mechanism that consists of the base chemistry from NUIGMech 1.1, with the addition of the NBD pyrolysis and oxidation reactions from recent efforts in the literature, was examined. The resulting numerical predictions do not reproduce the new results with satisfying agreement, and detailed chemical kinetic analyses were subsequently performed. Reaction pathways analysis shows that the NBD reacted as follows to form CO: NBD \(\to \) C–C5H6 \(\to \) C–C5H5 \(\to \) C3H3, where C3H3 can give HCO via two reactions, C3H3 + OH \(\rightleftharpoons \) C2H3 + HCO and C3H3 + O2 \(\rightleftharpoons \) CH2CO + HCO. The CO formation then comes from the reaction HCO + M \(\rightleftharpoons \) H + CO + M.