Aromatic compounds synthesis from cyclopentadiene or dicyclopentadiene was studied with platinum catalysts supported on zeolites under hydrogen atmosphere. It was revealed that aromatic compounds were not formed through cyclopentane and n-pentane, but they were primarily formed by C-C bond scission of bicyclic compounds such as methylindane and tetralin which were derived by the bridge-head C-C bond fracture of dicyclopentadiene. Selectivity to product was supposed to depend both on acidity of the zeolite and on the hydrogenation activity of platinum. The highest BTX yield, about 60%, was obtained on 0.5%Pt/H-ZSM-5.