Diglycidyl ether of 9,9-bis(4-hydroxyphenyl) fluorene (DGEBF) monomer was successfully synthesized and characterized in detail. The crystal structure of DGEBF was measured by single-crystal X-ray diffraction analysis. Curing kinetics of DGEBF with 4,4-diaminodiphenyl sulfone (DDS), thermal properties, and decomposition kinetics were investigated using nonisothermal differential scanning calorimetry (DSC) according to Kissinger, Ozawa and Crane methods. The glass transition temperature (T-g), thermal properties of cured polymer were estimated by DSC, dynamic mechanical analysis, and thermogravimetric analyses. Epoxy value of DGEBF monomer up to theoretical value leads to higher crosslink density of cured polymers. The cured DGEBF/DDS system exhibited obvious higher T-g and better thermal stability compared to those of DGEBF/diamine systems reported previously. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 827-833, 2010