[9] Ioxynil and bromoxynil (along with 2,4-DB and MCPB) were patented by Louis Wain as joint-head of the chemistry department at Wye College,[10] and coincidentally discovered independently by May & Baker in England screening spare nitriles for herbicide activity, and by Amchem Products Inc in America doing similar screening, all in 1963.

Commercial prospects were promising, as cereals could tolerate large amounts, over 2 lbs/ac;[11] even 4 lbs/ac only temporarily scorches.

[10]: 448-450 May & Baker, a subsidiary of Rhone-Poulenc began ioxynil's, and the very similar bromoxynil's, production in Norwich in 1965,[13][2] where it has continued for over 40 years.

[14] By 1968, ioxynil (as "Buctril") was registered for use in the USA, Canada, the UK, Australia, New Zealand, Japan, the West Indies and most of Europe.

[15] Today, ioxynil is banned in the EU and used in Brazil,[16] China (as octanoate),[17] New Zealand,[18] Australia, South Africa and Japan.

[21] Ioxynil is a flammable solid with a weak phenolic smell and decays under UV light.

In good conditions on small plants, necrosis may complete within two days but some weeds can take up to three weeks to die.

[2] Ioxynil is or has been sold under these tradenames: Ioxynil, Unyunox, Totril, Toxynil, Hawk, Hocks, Sanoxynil, Iotril, Certrol, Actril, Actrilawn, Bentrol, Belgran, Bronx, Cipotril, Dantril, Oxytril, Mextrol-Biox, Sanoxynil, Shamseer-2, Stellox, Iotox, Iconix and Trevespan.

[citation needed] It is used to control these weeds: bellvine, burr medic, capeweed, chickweed, climbing buckwheat, common heliotrope, common sowthistle, corn gromwell, dandelion, dead nettle, fat-hen, fumitory, green amaranth, green crumbleweed, bittercress, ox tongue, pigweed, potato weed, saffron thistle, scarlet pimpernel, shepherd's purse, slender celery, smallflower mallow, stagger weed, threecornered Jack, three flowered nightshade, turnip weed, Ward's weed, wild radish, wild turnip, wireweed,[4] annual sowthistle, cornbind, musky storksbill, willow weed, buttercup, field pansy, groundsel, plantain, speedwell, stinking mayweed,[5] the knotweed family broadly, in particular tartary buckwheat, the composite or sunflower family, chamomile, mayweed, some borages, fiddlenecks, gromwells[2] and prickly paddy melon.