By use of fluid-bed technology, direct hydrodealkylation of heavy oils was studied and a new process to produce high purity naphthalene and 2-methylnaphthalene was developed. As a basic research, catalyst activity, selectivity and stability for hydrodealkylation of heavy oil, hydrodealkylation reaction scheme and kinetics and coke formation kinetics and mechanism were investigated. Reaction rate constants were theoretically analyzed with fluid-bed consecutive reaction model. These research and analyses were utilized for optimization and design of the process. Pilot operation provided high yield and quality of the products which were suitable for synthesis of monomers for high performance polymers.