A thermosetting composition having: I) an unsaturated curable polyester comprising the residues of an α,β-unsaturated polycarboxylic acid compound, said α,β-unsaturated polycarboxylic acid compound having at least two carboxylic acid groups or at least one anhydride group, and having at least one unsaturation in a position that is α,β relative to a carbonyl group and not located on an aromatic ring; and II) a phenolic resin having at least one methylol group. The unsaturated curable polyester resin can be dispersed in water or dissolved in a solvent and is suitable for waterborne or solventborne coating compositions. Phenolic based crosslinking coating compositions that contain these unsaturated curable polyester resins are curable at elevated temperatures.