High molecular-weight aromatic polyamides were obtained from 1,5- and 2,6-bis-(4’-carboxy-4-phenylenoxy-sulfonyl)naphthalene by direct polycondensation reaction in N-methyl-2-pyrrolidone with various aromatic diamines, using triphenyl phosphite and pyridine as condensing agents. The polymers were characterized by elemental analysis, thermogravimetric analysis, differential scanning calorimetry, and infrared analysis. The polyamides, obtained in quantitative yield, possessed inherent viscosities in the range 0.42-1.70 dL/g, glass transition temperatures between 245-310 degrees C, and 10% weight loss temperatures in nitrogen and air above 435 and 424 degrees C, respectively. Most of the polymers were soluble in aprotic solvents. The effect of the structure on properties, such as solubility, T-g, and thermal behavior, were also studied.