Constructed in 1924 & designed by Chattanooga's most prolific architect - Reuben Harrison Hunt; it is more commonly known as the Maclellan Building. For more than 40 years, 721 Broad St. was the headquarters of the Provident Life and Accident Insurance Co. They outgrew their headquarters and moved in 1960 to the Fountain Square office building - now named Unum after a 1999 merger.
Source: Nooga.com 4/22/15
This large glass plate was carefully masked by the photographer to accentuate the building. Two types of coatings are used. One of a solid pink paste that is completely opaque, the other, a semi-transparent red tint, which in black & white printing - would have created a lighter overlay to the surrounding buildings. Here it's shown as scanned in color - thus the greenish tint.
The Chattanooga Public Library's collection includes a print from this negative, noting Matt L. Brown & Co is embossed on lower right corner of one copy.