(Z)-3-((4-Chloro-2-oxo-2H-chromen-3-yl)methyl)-5-(4-nitrobenzylidene)-2-thioxothiazolidin-4-one is a proposed intermediate in the synthesis of NSC 658497 (N926028), a novel inhibitor of SOS1-Ras interaction, dose-dependently inhibiting SOS1 GEF activity.