General view of Philadelphia Mayor James Tate (center) and two unidentified Rohm and Haas Company executives at the groundbreaking ceremony for the Rohm and Haas Company headquarters located on Independence Mall. Construction of the new headquarters, designed by architect Pietro Belluschi, began in 1963 as part of the city of Philadelphia's efforts to improve and revitalize the area around Independence Hall. Upon completion, Rohm and Haas, a manufacturer of specialty chemicals and materials including Plexiglas, relocated its headquarters from Washington Square in 1965.