Tetrasubstituted　olefins　as　a　pivotal　scaffold　have　been　extensively　employed　in　pharmaceuticals,　natural　products,　polymer　chemistry,　and　material　sciences　and　arouse　great　attention　in　chemical　com-munity.　Despite　advances　on　the　assembly　of　fully　carbon　tetrasub-stituted　olefins,　the　synthesis　of　tetrasubstituted　alkenyl　monoha-lides　are　underdeveloped　and　elusive.　Herein,　we　report　four　intriguing　migration　reactions　from　alkynyl　tetracoordinate　boron　species,　in　which　various　common,　inexpensive,　and　user-friendly　halogen　electrophiles　(Selectfluoro,　TCCA,　NIS,　and　NBS)　are　suit-able　electrophilic　halogen　sources.　Versatile　tetrasubstituted　ole-fins　were　thus　readily　accessible　from　transition-metal-catalyzed　transformations　of　these　newly　built　tetrasubstituted　alkenyl　mono　-halides　under　suitable　reaction　conditions.　The　mechanistic　investi-gations　suggest　that　different　electrophilic　halogen　sources　pro-mote　different　aryl　migration　routes　of　alkynyl　tetracoordinate　boron　species,　rendering　various　tetrasubstituted　alkenyl　monoha-lides,　respectively.　Distinct　reaction　modes,　unusual　mechanism,　valuable　products,　and　versatile　transformations　portray　the　advan-tages　and　significance　of　our　protocol.