A composite was prepared that contained diglycidyl ether of tetrabromobisphenol A (DGETBA) and 1,5-di(2,3-epoxypropoxy)naphthalene (A), 4,4'-bis(2,3-epoxypropoxy)benzylideneaniline (B), or 4,4'-bis(2,3-epoxypropoxy)biphenyl (C), and then was cured using different ratios of dicyandiamide (DICY). The results of DSC, TGA, coefficient of thermal expansion, dielectric constant, and dissipation factor testing of the composite epoxy resins were analyzed, and investigation of the copper-clad laminate using the composite epoxy resins as prepreg was also performed. Additionally, moisture absorption, peel strength, arc resistance, comparative tracking index, and flammability of the copper-clad laminate were examined. Clearly, some of the physical or mechanical properties of the composite and the copper-clad laminate can be improved by optimal addition of naphthalene-phenyl-based epoxy. (C) 2005 Wiley Periodicals, Inc.