2-Seleno-1-methylbenzimidazole, H(sebenzim Me ), can be synthesized from 1-methylbenzimidazole by sequential treatment with (i) Bu n Li, (ii) elemental selenium and (iii) HCl(aq). This method is also applicable to the synthesis of 2-seleno-1-t-butylbenzimidazole, H(sebenzimBut). Single crystal X-ray diffraction and NMR spectroscopic data demonstrate that H(sebenzim Me ) and H(sebenzimBut) exist as the selone rather than the selenol tautomers, which is in accord with the results of density functional theory (B3LYP) calculations. The data also indicate that the selone is best represented as a C + –Se − zwitterion rather than as a CSe doubly bonded species. Aerobic oxidation of H(sebenzim Me ) and H(sebenzimBut) in the presence of Et 3 N yields the diselenides, (sebenzim Me ) 2 and (sebenzimBut) 2 . In addition, H(sebenzim Me ) reacts with HgCl 2 to give [H(sebenzim Me )] 2 HgCl 2 , the first structurally characterized example of a 2-seleno-1-alkylimidazole mercury complex.