?2-[2-[2-Chloro-3-[(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)ethylidene]-1-cyclopenten-1-yl]ethenyl]-1,3,3-trimethylindolium iodide , its cas register number is 56289-67-9. It also can be called IR-786 iodide .