Unsaturated hydrocarbons are also used in many chemical reactions to synthesize other compounds. One of their utility in this area is to be used as monomers in polymerization reactions. In these reactions, simple monomer unit molecules react and bind with each other either linearly or nonlinearly to synthesize macromolecules, yielding either polymer chains or 3D structures. During polymerization, the double bond in the monomers usually turns into a single bond so that two other monomer molecules can attach on both sides. Some products of polymerization reactions are closely related to our daily life. For example, one of the common types of plastic, polyethylene, is the polymerization product of ethylene. Also, Styrofoam (polystyrene) is the synthesized from the polymerization of styrene.

Unsaturated hydrocarbons are widely used as pesticides, fuel, paints, and many other necessities. Below is a table of some common commercial unsaturated hydrocarbons.

Name	Structure	Use
ethene (ethylene)		Ripening of plants Monomers for synthesizing polyethylene
naphthalene		Common pesticide used to repel moth

For instance, naphthalene is a common pesticide used to repel moth.