Carbocation-initiated cascade [1,5]-hydride transfer/cyclization and dimerization reactions were developed to synthesize dihydrodibenzo[b,e]azepine and octahydrodipyrroloquinoline derivatives in high yields. These redox-neutral C(sp3)-H functionalization-involving cascade reactions feature transition-metal-free, high atom- and step-economy, and environmental friendliness with water as the sole byproduct.