The Matteson homologation, first developed in 1980, elongates carbon chains by insertion into a C−B bond. 1 This versatile reaction traditionally requires three steps: carbanion formation, nucleophilic addition to organoboron, and a thermo- or Lewis acid-promoted boronate rearrangement. These processes often demand exacting conditions, including cryogenic temperatures and handling of air- and moisture-sensitive reagents. 2,3 Here, we report a Matteson-type homologation which integrates these three transformations into a one-pot electrochemical process.