The condo building at 360 W. Illinois Street reads "JOHN SEXTON & CO."
John Sexton, born in Canada in 1858, came to Chicago in 1877. He was a grocer and developed a chain of tea and coffee stores. In 1883, he partnered with George Hitchcock to found the wholesale grocery company Hitchcock & Sexton. Three years later, Sexton became sole owner and the company became John Sexton & Co.
Its first home was on State Street, between Lake and what is now Wacker Drive. In 1908, the company moved to the Northeast corner of Lake and Franklin. It wasn't until 1915 that the company completed construction on this building and claimed it as its plant of operations. It was designed by Alfred S. Alschuler. In 1928, additions were made and the building grew to the size it is today. After signing off on the expansion, Sexton handed over the company to his sons and retired to Los Angeles on Thanksgiving 1929, but he died soon after of pneumonia on January 15, 1930.
The company eventually became Sexton Quality Foods. The Wikipedia article about the company - which is still technically in business today as US Foodservice - is quite extensive. Check it out if you have an hour today.