Cyclobutene is a cyclic hydrocarbon with the chemical formula C₄H₄. It consists of a four-membered ring containing one double bond, making it an example of an alkene. Cyclobutene is a colorless liquid at room temperature and is known for its unique reactivity due to the strain in its ring structure. This compound is used in organic synthesis and can serve as a building block for more complex molecules. Cyclobutene can undergo various chemical reactions, including polymerization, which allows it to be transformed into larger, more complex structures useful in materials science and pharmaceuticals.