Aromatic hydrocarbon growth from cyclopentadiene (CPD) was studied using a laminar flow reactor operating in the temperature range 550-950 degrees C without oxygen Benzene, indene and naphthalene were the major products which is in agreement with the previous computational studies on the reaction pathways from CPD A crossover of indene and naphthalene yields around 775 degrees C was also observed which further supports the results of the computational studies Although the specific intermediates in the proposed pathways from CPD were not detected the high selectivity of products and the observation of other methylindene and dihydronaphthalene intermediates suggest that the recombination of two CPDs via radical-molecule and/or radical radical pathways to form indene and naphthalene is the dominant formation pathway In addition to the products from the CPD CPD reactions the products from the reactions of CPD with indene naphthalene and acenaphthylene were also observed which demonstrate the importance of CPD in carbon growth