A diene is a type of organic compound that contains two double bonds between carbon atoms. These double bonds can be arranged in different ways, leading to various types of dienes, such as conjugated dienes, where the double bonds are separated by a single bond, and isolated dienes, where the double bonds are separated by more than one single bond. Dienes are important in organic chemistry and are often involved in reactions like polymerization, where they can form long chains of molecules. They are also found in many natural products and play a role in the synthesis of various chemicals.