An operationally simple deaminative borylation reaction of primary alkylamines has been developed. The formation of electron-donor acceptor complexes between N-alkylpyridinium salts and bis-(catecholato)diboron enables photoinduced single-electron transfer and fragmentation to carbon-centered radicals, which are subsequently borylated. The mild conditions allow a diverse range of readily available alkylamines to be efficiently converted into synthetically valuable alkylboronic esters under catalyst-free conditions.