A new soluble aramide with pendant phthalonitrile units was prepared, while its properties including solvent resistance and thermal properties can be enhanced by further thermal treatment around the glass transition temperatures of the polymers for an extended period of time. The cured polymers were characterized by thermogravimetric analysis, differential scanning calorimetry and FTIR techniques. Such improvement in polymer properties can be attributed to the nitrile cure reactions, indicated by the observation of the decrease in nitrile absorbance and the characteristic triazine band on the FTIR spectra. (C) 2009 Elsevier Ltd. All rights reserved.