A series of organosoluble aromatic cardo copolyamides (PA) with chlorine and carboxylic side groups has been synthesised by low‐temperature polycondensation in N‐methyl‐2‐pyrrolidone (N‐MP) solution and their properties have been estimated. The obtained polymers are differed in high molar masses (ηinh = 0.7 ÷ 1.8 dL/g) and demonstrate the following thermal characteristics: 300 °C < Tg < 390 °C; 425 °C < T10% < 510 °C (in air). PA films are characterized by high tensile strength (100 ÷ 230 MPa) and modulus (1.6 ÷ 2.3 GPa). It was stated the obtained PAs form the high quality coatings with good adhesion to the optical fiber surface without any additional coupling agent. The fibers with elaborated PA coatings demonstrate high thermal stability. The study of the optical fiber bending strength before and after thermal tests has shown that this parameter decreases by 10% only after prolonged exposure to high temperatures, namely, 72 h at 200–300 °C. Some samples withstand more than 1 h treatment at 350 °C without any changes of the optical fiber bending strength.