Abstract: This invention concerns monosubstituted dithiooxamides, and a preferred class comprises those wherein the substituent is such that the resulting dithiooxamide derivative is substantially nonvolatile at about room temperature. Preferred materials are those for which when the monosubstituent dithiooxamide is complexed with a transition metal cation, the resulting polymer is substantially a dark, i.e., preferably blue or blue-black color. Carbonless paper constructions involving use of N-(monosubstituted)dithiooxamides to advantage are described.