A series of aromatic polyamides and polyimides containing pendent pyrazole rings with amino and cyano groups were prepared from a new monomer, 1-(2,4-diaminophenyl)-3-phenyl-4-cyano-5-aminopyrazole, which was prepared from (chloromethylene)propanedinitrile and 2,4-dinitrophenyl hydrazine with two steps. In addition, model compounds were synthesized and characterized by elemental analyses, Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR) spectroscopy. The amino and cyano groups on the pyrazole ring were not affected during the polymerization process. The synthesized polymers, with intrinsic viscosities of 0.33-0.53dL/g, were soluble in various organic solvents. They showed no T-g values before degradation, and the 5% weight loss temperature of the polyamides and the polyimides occurred at approximately 420 and 470 degrees C, respectively. They also underwent no thermal transitions, such as degradation or crosslinking, up to 440 degrees C in spite of the presence of pendent amino and cyano groups.