General procedure for the synthesis of 4,4'-dinitro-1,1'-biphenyl-2,2'-dicarboxylic acid (DNBPDC) from the compound (CAS: 863305-32-2): 12.1 g of DPA (diphenylacetylene) was dissolved in 75 mL of concentrated sulfuric acid, and 25 mL of fuming nitric acid was slowly added at a temperature of less than 50 °C. The reaction was completed by stirring for 10 minutes. After addition, the reaction mixture was continued to be stirred for 10 minutes, followed by a rapid temperature increase to 60 °C, and the reaction was maintained at this temperature for 2 hours. Upon completion of the reaction, the mixture was carefully poured into a small amount of crushed ice. After a few hours, the resulting light yellow solid was collected by filtration, washed with water and dried at 60 °C to give 14.2 g DNBPDC. the product has a melting point of 236 °C (decomposition). The compound is insoluble in ether, chloroform and cold water, but soluble in ethanol and DMF.When recrystallized from DMF at high temperature, very fine needle-like crystals were obtained. Elemental analysis results (calculated value, C16H15N3O8): C, 50.93%; H, 4.01%; N, 11.14%. Measured values: C, 50.90%; H, 3.99%; N, 11.05%. Infrared spectra (IR) characteristic absorption peaks: νas(CO2-) 1709 (s) cm-1, νs(NO2) 1344 (s) cm-1, νas(NO2) 1533 (m) cm-1.