1,12-Dodecanedicarboxylic acid, also known as tetradecanedioic acid, is a long-chain aliphatic dicarboxylic acid with the molecular formula C₁₄H₂₆O₄. It is a white crystalline powder at room temperature. Its primary industrial application is as a monomer in the production of specialty polyesters, polyamides (nylons), and other high-performance polymers. The long, flexible methylene chain between the two terminal carboxyl groups imparts desirable properties to the resulting polymers, such as flexibility, toughness, and chemical resistance. It is used to synthesize engineering plastics, coatings, and hot-melt adhesives. It also serves as a key intermediate in the synthesis of fragrances, lubricants, and corrosion inhibitors. As a linear dicarboxylic acid, it is a versatile organic synthesis building block for constructing longer carbon chains or for introducing carboxyl functionalities. It is considered a bio-based platform chemical with potential in sustainable material development.