A novel cycloaliphatic triepoxide, 1,1-bis(2',3'-epoxycyclohexyloxymethyl)-3,4-epoxycyclohexane (II), and its precursor, 1, 1-bis(2 ' -cyclohexenyloxymethyl)-3-cyclohexene, were synthesized. Their chemical structures were confirmed with IR spectroscopy, elemental analysis, and H-1 NMR spectroscopy. 11 was easily cured with hexahydro-4-methylphthalic anhydride with 1,3,5-triethylhexahydro-s-triazine as a curing accelerator. The physical properties of the cured product were examined with thermomechanical analysis, thermogravimetric analysis, and dynamic mechanical analysis. Compared with the commercial diepoxide ERL-4221 under the same curing conditions, the cured product based on II showed a much higher glass-transition temperature (198 degreesC), a higher crosslinking density (2.08 X 10(3) mol/cm(3)), and a lower coefficient of thermal expansion [6.2 X 10(5)(/degreesC)]. II may become a promising candidate material for modern microelectronic packaging.