Phenylenediamine may refer to: o-phenylenediamine or OPD, a chemical compound C6H4(NH2)2 m-phenylenediamine or MPD, a chemical compound C6H4(NH2)2 p-phenylenediamine or PPD, a chemical compound C6H4(NH2)2 N,N-dimethyl-p-phenylenediamine or DMPD N,N,N′,N′-tetramethyl-p-phenylenediamine or TMPD, used in microbiology N,N-diethyl-p-phenylenediamine or DPD Diamines