The scope of direct substitution of the dithiolene ligand from [M(S2C2Ph2)(2)] [M = Ni2+ (1), Pd2+ (2), Pt2+ (3)] to produce heteroleptic species [M(S2C2Ph2)(2)L-n] (n = 1, 2) has been broadened to include isonitriles and dithiooxamides in addition to phosphines and diimines. Collective observations regarding ligands that cleanly produce [M(S2C2Ph2)L-n], do not react at all, or lead to ill-defined decomposition identify soft sigma donors as the ligand type capable of dithiolene substitution. Substitution of MeNC from [Ni(S2C2Ph2)-(CNMe)(2)] by L provides access to a variety of heteroleptic dithiolene complexes not accessible from 1. Substitution of a dithiolene ligand from 1 involves net redox disproportionation of the ligands from radical monoanions, (-SSC2Ph2)-S-center dot, to enedithiolate and dithione, the latter of which is an enhanced leaving group that is subject to further irreversible reactions.