Diamines　play　important　roles　in　synthetic　organic　chemistry　and　thus　facilitate　life　and　materials　sciences.　Herein　we　report　a　cobalt-catalyzed　ring　opening,　nucleophilic　amination　of　aziridines　and　azetidines　with　N-fluorosulfonamides　toward　a　wide　range　of　1,2-　and　1,3-diamine　derivatives　in　moderate　to　good　yields　under　mild　conditions.　A　cobalt-catalyzed　ring　opening,　nucleophilic　amination　of　aziridines　and　azetidines　with　N-fluorosulfonamides　has　been　established　toward　a　wide　range　of　1,2-　and　1,3-diamine　derivatives　in　moderate　to　good　yields　under　mild　conditions.