Herein,　we　report　a　biomimetic　oxidative　coupling　cyclization　strategy　for　the　highly　efficient　functionalization　of　tetrahydrocarbolines　(THCs).　This　process　enables　rapid　access　to　complex　isochromanoindolenine　scaffolds　in　moderate　to　excellent　yields.　The　reaction　proceeds　smoothly　and　rapidly　(complete　within　minutes)　in　an　open　flask.　This　operationally　simple　protocol　is　scalable　and　compatible　with　a　wide　range　of　functional　groups.　Late-stage　functionalization　of　a　pharmacologically　relevant　molecule　is　also　demonstrated.