Fomesafen is an N-sulfonylcarboxamide that is N-(methylsulfonyl)benzamide in which the phenyl ring is substituted by a nitro group at position 2 and a 2-chloro-4-(trifluoromethyl)phenoxy group at position 5. A protoporphyrinogen oxidase inhibitor, it was specially developed for use (generally as the corresponding sodium salt, fomesafen-sodium) for post-emergence control of broad-leaf weeds in soya. It has a role as a herbicide, an agrochemical and an EC 1.3.3.4 (protoporphyrinogen oxidase) inhibitor. It is an aromatic ether, a N-sulfonylcarboxamide, a C-nitro compound, an organofluorine compound, a member of monochlorobenzenes and a member of phenols. It is a conjugate acid of a fomesafen(1-).