The 13th-seeded Jankovic, who won the Cincinnati title in 2009, was ousted by China's Peng Shuai in a marathon 5-7, 7-5, 7-6 (10-8) battle.
Jankovic failed to convert on numerous match points in a bout delayed by rain in the final set.
Meanwhile, ex-French Open titlist Schiavone, seeded 14th, fell to wild card and fellow Italian Camila Giorgi 6-1, 6-3 at the Lindner Family Tennis Center.
Also Monday, 11th-seeded Slovakian Dominika Cibulkova advanced with a 6-4, 6-4 decision over Uzbekistan qualifier Akgul Amanmuradova.
Germany's Mona Barthel and Polish qualifier Urszula Radwanska also advanced with victories.
Members of Congress to keep receiving porn magazine
Justin Bieber crashes Drake Bell's album release party