Taikyu Ree (1902-92) and Seung Ki Li (1905-96) were the most famous and influential scientists in twentieth-century Korea. Trained at Kyoto Imperial University during the Japanese occupation period (1910-45), both followed parallel career paths until 1945 but after that year those paths began to diverge. In 1948 Taikyu Ree moved to the University of Utah where he ran an informal graduate programme to train Korea chemists during the 1950s and 1960s. He became a model scholar in pursuit of knowledge for its own sake. In 1950 Seung Ki Li moved to North Korea where he succeeded in industrialising a new synthetic fibre from polyvinyl alcohol. He became a popular hero who demonstrated the utility of science. His success also helped Kim Il Sung, North Korea dictator, to consolidate his political ideology of Self-Reliance. Despite their different career patterns in very different circumstances, they shared something common; apolitical views and commitment to their work. An investigation of the careers of these two chemists illustrates the interwoven scientific, ideological and economic developments of South and North Korea during the second half of the twentieth century.