1,1'-((4,4,7,7-tetramethyl)-4,7-diazaundecamethylene)bis-4-(3-methyl-2,3-dihydro(benzo-1,3-oxazole)-2-methylidene)quinolinium [ 1,1'-((4,4,7,7-tetramethyl)-4,7-diazaundecamethylene)bis-4-(3-methyl-2,3-dihydro(benzo-1,3-oxazole)-2-methylidine)quinolinium, tetraiodide,YOYO,YOYO-1 ] non-fluorescent in solution but forms highly fluorescent complex with double-stranded DNA; RN refers to the tetraiodide compound