A general and atom-economical electrochemical dehydrogenative method for the intermolecular 1,2-alkylarylation of styrenes with malonates and nucleophilic N-heteroarenes (including indoles and pyrroles) has been developed. This transformation provides a regioselective route to construct highly valuable 1,1-diarylalkanes enabled by C(sp3)-H/C(sp2)-H functionalization under mild conditions, and H2 is the only theoretical byproduct. Mechanistic studies indicated that the reaction proceeded through the oxidative of the C(sp3)-H bond to generate alkyl radical, radical addition across the C═C bond, single electron oxidation and C(sp2)-H functionalization cascades.