A series of coordination compounds of platinum(II) and palladium(II) with several amino- and heterocyclic aminoalkyl mercaptans was synthesized, and their structures were determined by IR absorption and elemental analyses. Because of the tendency of the mercapto group to undergo oxidation on reaction with metals, as observed with copper(II), the complexes were obtained by use of the aminoalkylthiosulfates, which decomposed to the thiol in either acid or alkaline solution. Furthermore, palladium-sulfide complex formation by reaction with an aminoalkyltrithiocarbonate made it possible to distinguish between metal-sulfur and metal-nitrogen bonds in the 650--400-cm-1 region. Anticancer screening against L-1210 lymphoid leukemia in mice did not reveal positive activity among the compounds tested.