Thomas L. Jennings
Thomas L. Jennings (1791–1856) was an African American tradesman and abolitionist. He was a free black who operated a dry-cleaning business in New York City, New York and was the first African American to be granted a patent. Jennings' skills along with a patent granted by the state of New York on March 3, 1821 for a dry cleaning process called "dry scouring" enabled him to build his business. He spent his early earnings on legal fees to purchase his family out of slavery, and supporting the abolitionist movement. In 1831, Jennings became assistant secretary to the First Annual Convention of the People of Color in Philadelphia, Pennsylvania, which met in June, 1831.
Patent Controversy 
Jennings' patent resulted in a considerable amount of controversy. The U.S. patent laws of 1793 stated that "the master is the owner of the fruits of the labor of the slave both manual and intellectual," thus slaves could not patent their own inventions, the efforts would be the property of their master. Thomas Jennings was able to gain exclusive rights to his invention because of his status of being a free man. In 1861 patent rights were finally extended to slaves.
Further reading 
Joan Potter, African American Firsts (New York: Kensington Publishing Group, 2002)