Indoline‐fused polycyclic scaffolds are virtually universal in biological and pharmaceutical. Here we demonstrate a facile electrooxidative cascade cyclization for indoline‐based derivatives, employing amidyl radicals with ynones under mild conditions. The efficient method enables the formation of two new C−N and C−C bonds in a single step with high regioselectivity. Various indoline‐based tetracyclic 6/5/6/6 skeletons can be achieved through a biscyclization/dehydrogenation cascade process. Additionally, this electrochemical strategy proceeds in a sustainable metal‐ and oxidant‐free condition, with H2 being the solely byproduct. [ABSTRACT FROM AUTHOR]