Sulfur extraction from the tripeptide thiol, glutathione (α‐glu‐cys‐gly) (1) via reaction with syn‐(1‐bromo‐ethyl, methyl)bimane (2) yields glutathione slfide and the thiabridged bimane, μ(S)‐syn‐(methylmethylene, methyl)bimane (3) . The reaction with 2 has been extended to dithiols as models for important biological thiols such as reduced trypanothione. The fluorescent dithiols were derived through reductive cleavage with triphenylphosphine (tetrahydrofuan, Hcl−Kbr solution, pH 1.5) of the dithiatriclic bimane esters, μ(O2C(CH2)SS(CH2)nCO2)‐syn‐(CH2,CH3)B, n = 1, 2, 3, prepared from syn‐(bromomethyl, methyl)bimane (4) and the corresponding dithiadicarboxylic acids. Sulfur extraction led to 3 and the cyclic sulfide derived from the dithiol in moderate yields. The dithiols, dithiothreitol and dithioerythritol, also yielded moderate amounts of 3. Sterically hindered thiols (e.g., those in hemoglobin) gave 3 in lower yields. Treatment of human red blood cells and red cells membranes (hemoglobin‐free ghosts) with 2 gave rise to some 3. A side product in some reactions was the oxabridged bimane, μ(O)‐syn‐(methylmethylene, methyl)bimane.