A novel di-carboxylic acid curing agent (DACA) was successfully synthesized and cured with three different epoxy resins: glycidyl end-capped poly(bisphenol-A-co-epichlorohydrin) (pDGEBA, M-n = 377), N,N-diglycidyl-4-glycidyloxyaniline (TGAP), and 4,4 '-methylenebis(N,N-diglycidylaniline) (TGDDM). The cured epoxy exhibited excellent thermal stability, which was indicated by high initial degradation temperature (T-id) and char yield. The T-id values of cured epoxy were in the range of 327-338 degrees C, and the char yields increased with increasing epoxy functionality. The char yields of cured DACA/pDGEPA, DACA/TGAP, and DACA/TGDDM samples were 21.1, 60.4, and 66.9%, respectively. In addition, the cured epoxy samples also showed low coefficients of thermal expansion and high storage moduli (E '), which were around 60 ppm/degrees C and 2800 MPa, respectively. The failure surfaces were ductile and rough, so the cured epoxy samples are expected to have high fracture toughness and impact strength. POLYM. ENG. SCI., 54:695-703, 2014. (c) 2013 Society of Plastics Engineers