A new method was developed to synthesize tetradentate ligands containing the N,N''-bis(S-benzoylmercaptoacetyl) ethylenediamine and propylenediamine moieties (DADS compounds). Methods are also represented with which to synthesize some of the positional isomers of the above compounds. These isomers represent a new class of compounds. A total of 21 different compounds were prepared. These will be used in an effort to establish a relationship between structure and renal imaging properties.