Abstract: The synthesis,formulation and characterizations of two new diepoxides were reported,one diepoxide contains tertiary ester（EP-1） and the other contains tertiary ether linkages（EP-2）.Both compounds were characterized with 1H-NMR and FT-IR and formulated into underfill materials with an anhydride as hardener and a 2-methylimidazole as catalyst.A dual-epoxy system（EP-3） was also formulated with the tertiary ester diepoxide and a conventional aliphatic diepoxide,ERL-4221,using the same hardener and catalyst.The thermogravimetric analysis（TGA） reveals that the cured EP-2 and EP-3 had obviously lower thermal decomposition onset temperature（around 215℃） than ERL-4221（310℃）.The shear strength and glass transition temperatures of these novel diepoxides decreas quickly upon being aged at 225℃.The unusual thermal degradable properties make these compounds a potential use as reworkable underfill for flip-chip application.