Azodicarboxylic acid is a chemical compound with the formula C₄H₄N₂O₄. It appears as a white crystalline solid and is primarily used in the production of various polymers and as a chemical intermediate in organic synthesis. This compound contains two carboxylic acid groups, which contribute to its reactivity and versatility in chemical reactions. In addition to its industrial applications, azodicarboxylic acid is also utilized in the preparation of azodicarbonamide, a blowing agent in the production of foamed plastics. Its ability to decompose and release nitrogen gas makes it valuable in creating lightweight materials.