RuBP-2S (Ruthenium(bis(bathophenanthroline))(bathophenanthrolinedisulfonate) is a luminescent ruthenium complex similar to RuBPS. Two of the bathophenanthroline ligands are neutral while the third bathophenanthroline ligand is bis-sulfonated, resulting in an overall neutral charge of the ruthenium complex. RuBP-2S shares the spectral properties of RuBPS and may also have similar applications.