In 2011, San E released several singles, including “Please Don't Go," a collaboration with rapper Outsider and singer Lee Changmin (of 2AM). The song reached #14 on the Gaon Digital Chart, making it his highest charted song while contracted under JYP Entertainment. He also collaborated that year with Verbal Jint, Beenzino, Swings, and other artists on the single "Stand Up, Japan!" which benefited Japan's relief efforts after the Tohoku tsunami.