Carbon-carbon coupled dimers of N-arylnaphthylamines are prepared by thermally decomposing an N-nitroso-N-arylnaphthylamine. The aryl portion of such material may be phenyl, naphthyl or an alkyl-, alkoxy- or halogen-substituted member of these. The compounds thus produced are useful as antioxidants for a variety of organic materials. These include polyurethane and polyolefin polymers as well as lubricating oils.