Entropy‐Induced Selectivity Switch in Gold Catalysis: Fast Access to Indolo[1,2‐a]quinolines

New N‐heterocyclic compounds for organic functional materials and their efficient syntheses are highly demanded. A surprising entropy‐induced selectivity switch in the gold‐catalyzed intramolecular hydroarylation of 2‐ethynyl N‐aryl indoles was found and its exploitation led to straightforward syntheses of indolo[1,2‐a]quinolines. Experimental and computational mechanistic investigations gave insight into this uncommon selectivity phenomenon and into the special reactivity of the indolo[1,2‐a]quinolines. The high functional group tolerance of this methodology enabled access to a diverse scope with high yields. In addition, bidirectional approaches, post‐functionalization reactions, and π‐extension of the core structure were feasible. An in‐depth study of the photophysical properties explored the structure‐effect relationship for different derivatives and revealed a high potential of these compounds for future applications as functional materials.