The scientific instrument maker said the deal will expand its business in the Asia-Pacific region and help it do more business in industries such as environmental analysis, water testing, and food safety.
It is Thermo Fisher's second deal in the last few weeks that targets growth in Asia and the Pacific. On Nov. 30, the company said it agreed to buy Lomb Scientific, which sells laboratory chemicals, consumables, and instruments in Australia and New Zealand.
Thermo Fisher said the purchase will close in the first quarter of 2011 and raise its profit by 13 cents to 15 cents per share over the first year after closing. It expects the sale to create $60 million per year in savings by the third year. Dionex will become part of its analytical technologies business.
The Waltham, Massachusetts, company will pay a $118.50 a share, a 20.7 percent premium over Friday's Dionex closing price. Dionex shares rose $19.36, or 19.7 percent, to $117.53 in pre-market trading.
The boards of both companies have approved the deal.
Dionex is based in Sunnyvale, California, and has 1,600 employees in 21 countries. It reported $419.6 million in revenue in its latest fiscal year, which ended June 30.
Thermo Fisher had 35,400 employees at the end of 2009, and it expects $10.72 billion to $1.8 billion in revenue in 2010.
