A 2,6-dimethyl phenol-dipentene adduct was synthesized from dipentene (DP) and 2,6-dimethyl phenol, and then a 2,6-dimethyl phenol-DP epoxy was synthesized from the reaction of the resultant 2,6-dimethyl phenol-DP adduct and epichlorohydrin. The proposed structures were confirmed by Fourier transform infrared, elemental analysis, mass spectra, NMR spectra, and epoxy equivalent weight titration. The synthesized 2,6-dimethyl phenol-DP adduct was cured with 4,4-diamino diphenyl methane, phenol novolac, 4,4-diamino diphenyl sulfone, and 4,4-diamino diphenyl ether. The thermal properties of the cured epoxy resins were studied with differential scanning calorimetry, dynamic mechanical analysis, dielectric analysis, and thermogravimetric analysis. These data were compared with those for the bisphenol A epoxy system. The cured 2,6-dimethyl phenol-DP epoxy exhibited a lower dielectric constant (ca. 3.1), a lower dissipation factor (ca. 0.065), a lower modulus, lower thermal stability (5% degradation temperature = 366-424 degreesC), and lower moisture absorption (1.21-2.18%) than the bisphenol A system but a higher glass-transition temperature (ca. 173-222 degreesC) than that of bisphenol A system.