A tin-based solder melt or aqueous tin plating bath composition comprising a source of tin and a stabilizing additive of chemical structure: wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are independently selected from hydrogen atom, hydrocarbon groups R having at least one and up to twelve carbon atoms, groups OR′ wherein R′ is selected from hydrogen atom and hydrocarbon groups R, and halogen atoms, and wherein any two, three, or four of R1, R2, R3, R4, and R5 or any two, three, or four of R6, R7, R8, R9, and R10 are optionally interconnected to form a fused ring system; R11 and R12 are independently selected from hydrogen atom and hydrocarbon groups R; and r is either 0 or 1. Methods for coating and/or bonding metal substrates by use of the above-described solder compositions are also described.