Complex sentence: In 1917 Sennett gave up the Keystone trademark and organized his own company, Mack Sennett Comedies Corporation, producing longer comedy short films and a few feature-length films.
Split into simpler sentences: In 1917 Sennett gave up the Keystone trademark and organized his own company, Mack Sennett Comedies Corporation. Sennett went on to produce more ambitious comedy short films and a few feature-length films.