Billionaire hedge funder Bill Ackman has kicked off his $260 million play to establish a brain research institute on Manhattan’s Upper West Side.

Pershing Square Foundation, the philanthropic arm of Ackman’s fund, dropped $188 million to acquire 125 West End Avenue, according to city documents filed Tuesday. The 400,000-square-foot life sciences building planned for the site will eventually host Ackman’s massive brain research center, the Ackman Oxman Institute, Fortune first reported.

The sale by Taconic Partners reportedly precedes another in-contract sale for the neighboring building, 320 West 66th Street, for roughly $70 million. Together, the acquisitions would secure Pershing Square Foundation an estimated 700,000 square feet of research and office space between West 65th and West 66th streets.

Ackman told Fortune that the charitable venture was inspired by his 26-year-old daughter, Lucy, who previously suffered a brain hemorrhage, as well as his wife, Neri Oxman, who lost her mother to Alzheimer’s disease. 

Pershing Square Foundation has teamed up with Mount Sinai Hospital System to develop the research institute, although the development timeline is unclear. 

The life sciences and office spaces at 125 West End Avenue, also called West End Labs, appear largely vacant, according to the building’s website. 

The building belongs to a 3.4-acre campus, known as West End Campus, sold to Taconic by Silverstein Properties for $230 million in 2019. West End Campus also includes 320 West 66th Street and a vacant parcel. 

Taconic repositioned the campus as a purpose-built research and laboratory complex. Its previous lives include the American Broadcasting Company (ABC)’s former campus, a Chrysler Motor Company facility and printing facilities for The New York Times.

Spokespeople for Pershing Square Foundation and Taconic did not immediately respond to requests for comment.  

Emily Davis can be reached at edavis@commercialobserver.com.