Dupont is buying the Danish food ingredients maker Danisco for $5.8bn (£3.7bn) as it looks to broaden its food and biofuels operations.
The acquisition also includes the assumption of $500m in debt.
Danisco, which is already a joint venture partner with DuPont in the development of cellulosic ethanol technology, said that it would recommend shareholders accept the deal.
Founded in 1802, DuPont has long been known for its chemicals business. But the American company has been trying to expand its operations.
In December, chief executive Ellen Kullman said 30 per cent of the company's 2010 sales – about $9bn – would come from products introduced in the past four years.
DuPont has been helped by growth in demand for its products used in agriculture and by the improving global economy, particularly in Asia. The company makes chemicals used in farming, electronics, autos and other industries.
Mrs Kullman said in a statement that Danisco is complementary to DuPont's biosciences business.
Danisco, listed on the Copenhagen, stock exchange, makes enzyme and specialty food ingredients. Its ingredients are used in a wide range of industries from bakery, dairy and beverages to animal feed, laundry detergents and bioethanol. The firm has nearly 7,000 employees.
Danisco's chairman Joergen Tandrup said that there were several bidders for the company, with DuPont coming out ahead late last night.
The acquisition is expected to close early in the second quarter and add to DuPont's 2012 earnings. It will finance the deal about $3bn cash and the rest in debt.