The plant was constructed within a year of the company signing a Memorandum of Understanding with the state government at the last year's Vibrant Gujarat Summit.
A government press release said the plant was built at a cost of Rs 1,000 crore and is spread over 23.44 hectares.
Executive Director of BASF (South Asia) Michael Heinz announced that the company was going to invest 10 billion pounds in the Asia-Pacific region during 2013 to 2020.
The Dahej plant will produce polyurethane, care chemicals and polymer dispersion.
The state was a leader in manufacturing of textiles, chemicals, pharmaceuticals, engineering products, oil and gas, jewelry and agro based products, she said, adding that Gujarat was now known as 'petro capital' of India with about 6,600 chemical and petro-chemical production units.
She credited Prime Minister Narendra Modi for encouraging the petrochemical sector in Gujarat when he was the Chief Minister.