20 Lira Oktay Sinanoğlu

Oktay Sinanoğlu, the Turkish-American chemist who turned down a tenured position at Yale in 1963 to return to Turkey, became a nationalist cause célèbre as much as a scientific one — his decision was publicly framed as a rejection of American academic dominance. He went on to develop the Many-Body Problem theory and held a joint appointment at Istanbul and Yale for years, a compromise that satisfied neither camp entirely. This commemorative follows a broader Darphane program issuing silver 20 Lira pieces honoring Turkish scientists and intellectuals, a series that accelerated noticeably after 2020.