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