Herein, we present an unprecedented electrochemical reductive cyclizative carboxylation of o-vinylphenyl isocyanides with carbon dioxide achieved without the use of metal catalysts. This protocol demonstrates a broad substrate scope and good functional group tolerance, facilitating the rapid assembly of 2-oxoindolin-3-acetic acids in good to high yields with excellent regioselectivity. Furthermore, these structural motifs may have potential applications in formal synthesis of bioactive natural products.