Atomic carbon and its corresponding masked analogues are exceedingly underexplored intermediates in synthesis. Despite this, these reagents possess inimitable reactivity such as the ability to directly insert carbon atoms into aromatic frameworks while simultaneously generating an additional bond at the carbon center to further diversify the structure. Herein, we report the design of the orthogonally reactive atomic carbon equivalent Cl-DADO and demonstrate its application to the molecular editing of indole and pyrrole, accessing linchpin-containing ring-expanded heterocycles that can be subsequently derivatized. The value of this approach and the broad applicability of this reagent are highlighted by the late-stage skeletal editing of numerous natural products and drug molecules.