Dinitrophenyl is any chemical compound containing two nitro functional groups attached to a phenyl ring. It is a hapten used in vaccine preparation. Dinitrophenyl does not elicit any immune response on its own and it does not bind to any antigen. Dinitrophenyl is any chemical compound containing two nitro functional groups attached to a phenyl ring. It is a hapten used in vaccine preparation. Dinitrophenyl does not elicit any immune response on its own and it does not bind to any antigen.