May 03, 2012. /Lesprom Network/. The Board of Directors of Koppers Holdings Inc. declared a quarterly dividend of $0.24 per common share, payable July 9, 2012, to stockholders of record as of the close of business on May 15, 2012. Koppers, with corporate headquarters and a research center in Pittsburgh, Pennsylvania, is a global integrated producer of carbon compounds and treated wood products.