TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The copolymer is phenylbenzimidazole-containing copolymer of formula (6). The tetracarbonyl compound is of formula (4), and dialdehyde compound is of formula (5).R2,R3=R1;andm,n=6-150.Preferred Process: An excessive quantity of tetraamine compound is reacted with tetracarbonyl compound to obtain mixture of oligomer having quinoxaline structure and tetraamine compound, and dialdehyde compound is reacted with resulting compound in presence of electroconductive carbon material and oxidizing agent, and spin-drying copolycondensation is carried out to obtain composite. An excessive quantity of tetraamine compound is reacted with dialdehyde compound in presence of oxidizing agent to obtain mixture of oligomer having phenylbenzimidazole and tetraamine compound, and tetracarbonyl compound is reacted with resulting compound in presence of electroconductive carbon material, and spin-drying copolycondensation is carried out to obtain composite. An excessive quantity of tetraamine compound is reacted with tetracarbonyl compound in presence of electroconductive carbon material to obtain mixture of oligomer having quinoxaline and tetraamine compound and electroconductive carbon material, and dialdehyde compound is reacted with resulting compound in presence of oxidizing agent, and spin-drying copolycondensation is carried out to obtain composite. An excessive quantity of tetraamine compound is reacted with dialdehyde compound in presence of electroconductive carbon material and oxidizing agent to obtain mixture of oligomer having phenylbenzimidazole and tetraamine compound and electroconductive carbon material, and tetracarbonyl compound is reacted with resulting compound, and spin-drying copolycondensation is carried out to obtain composite. The manufacturing process of composite further comprises filtering reaction mixture and washing reaction mixture by alcohol solvent, after spin-drying process. Polymerization process is carried out in presence of solvent. Preferred Property: The concentration of monomer containing tetracarbonyl compound, dialdehyde compound and tetraamine compound in solvent during initial stage of polymerization is 5-40 mass%. Preferred Components: The solvent is N,N-dimethylformamide. The tetracarbonyl compound is aromatic tetracarbonyl compound, preferably bis-(phenyl glyoxyloyl)benzene. The dialdehyde compound is aromatic dialdehyde compound, which is terephthalaldehyde and isophthalaldehyde. The tetraamine compound is aromatic amine compound, which is 3,3'-diaminobenzidine. The oxidizing agent is air. The electroconductive carbon material is Ketchen Black. Preferred Condition: The polymerization process is carried out at 100-150 degrees C. EXAMPLE - N-dimethylformamide (in g) (600), bisbenzyl (24.16), terephthalaldehyde (4.83) and 3,3'-diaminobenzidine (DABZ) (23.66) were mixed and stirred for 10 minutes, and reacted at 130 degrees C for 20 hours. Then, Ketchen Black (18.5) was added to resulting mixture, filtered, and the resulting mixture was washed using methanol and vacuum-dried to obtain polyphenylquinoxaline/polybenzimidazole copolymer/Ketchen Black composite having molecular weight of 27000.