Citrus　canker,　induced　by　bacterial　infection,　seriously　affects　the　growth　and　productivity　of　citrus　around　the　world　and　has　attracted　strong　research　interest.　The　current　treatment　for　this　disease　uses　copper　salts　to　inactivate　the　pathogenic　bacteria:　Xanthomonas　citri　subsp.　citri　(Xcc)　strain.　However,　copper　salts　may　have　a　negative　impact　on　the　environment　or　plant.　In　this　work,　we　identify　a　chemical　compound,　2,6-diiodo-1,3,5,7-tetramethyl-8-(P-benzoic　acid)-4,4　＇-difluoroboradiazaindacene　(DIBDP),　to　inactivate　the　pathogenic　Xcc　strain　(29-1).　DIBDP　is　activated　by　sunlight　and　generates　reactive　oxygen　species　to　kill　the　bacteria.　In　order　to　overcome　the　degradation　of　DIBDP　under　sunlight,　an　adjuvant　agent　was　identified　to　limit　the　photodegradation　of　DIBDP　by　forming　a　photosensitizer　complex　(PSC).　This　complex　demonstrated　significant　antimicrobial　activity　to　Xcc　29-1,　which　was　64-fold　more　potent　than　the　copper　biocides.　The　antimicrobial　efficacy　of　PSC　on　citrus　leaves　infected　by　Xcc　29-1　also　was　much　stronger　than　copper　agent　and,　at　the　same　time,　the　PSC　was　safe　to　the　host　exposed　to　sunlight.　Thus,　this　PSC　is　a　promising　antibacterial　agent　to　control　citrus　canker　disease.