Which Chicago architect is known for his innovative use of concrete?

Harry Weese is recognized for his innovative use of concrete in his architectural designs. He was a significant figure in promoting the use of reinforced concrete, which allowed for greater flexibility in design and structural integrity in buildings. Weese's work often showcased the versatility and aesthetic potential of concrete, making it a defining material in several of his prominent projects in Chicago. His approach contributed to the mid-century modern movement and influenced how concrete could be utilized in both public and private buildings.

While Louis Sullivan is known as the father of the skyscraper and made significant contributions to modern architecture, his primary focus was not on concrete but rather on ornamentation and form. Frank Lloyd Wright is celebrated for his designs and incorporation of natural materials, particularly wood, and for his concept of organic architecture. Walter Gropius, although influential in modern architecture and design through the Bauhaus movement, did not primarily focus on concrete innovations within the Chicago context. Thus, it's Weese's specific and innovative application of concrete that sets him apart in this question.