AbstractHere we report the C−C bond cleavage through the reaction of tetrahydroisoquinolines (THIQs) or indoles with activated olefins. THIQ reacts with olefins under catalyst‐ and solvent‐free condition resulting the formation of N‐benzyltetrahydroisoquinoline via the C−C bond cleavage followed by reduction of iminium ion. Here, THIQ behaves as a reducing agent. On the other hand, when indole is used in place of THIQ in presence of ceric ammonium nitrate as catalyst under solvent‐free condition, symmetrical bisindolylmethanes (BIMs) are obtained. The methodology could be further extended to synthesize unsymmetrical BIMs.