Photothermographic elements employing improved base precursors that undergo thermal decomposition are disclosed. Thermal-dye-bleach agents, and in particular, a novel class of salts of arylsulfonylacetic acids as bleaching agents for photothermographic use are disclosed. Photothermographic elements employing these thermal-dye-bleach agents are suitable for use as acutance and antihalation systems, bleachable filter dye materials, and in promoting unblocking of various components such as blocked developers, especially in photothermographic elements.