TOLEDO, Ohio — The realization was as surprising as it was momentous. Toledo, long known as Glass City, needed glass, and it could no longer be manufactured here quickly enough.

So Toledo turned to China to make the 360 panels, 1,300 pounds each, needed for an extension to the Toledo Museum of Art. Some here resented the move after China supplanted the United States as the world’s top glass producer. But in the process, city leaders began an improbable and remarkable relationship.

Over the past seven years since the museum project was completed, ties between Toledo and China have grown numerous. Chinese companies have paid more than $10 million in cash for two local hotels, a restaurant complex and a 69-acre waterfront property. Mayor Michael P. Bell has taken four trips to China in four years in search of investors. His business cards are double-sided, in English and Chinese.

Huaqiao University, one of the largest higher-education institutions in China, recently signed an agreement to open a branch in Toledo. There have also been preliminary talks between local officials and a Chinese company about an arrangement in which industrial tools would be produced in China, shipped for assembly in Toledo and labeled “made in the U.S.A.,” which would allow them to be sold at a premium.