The photothermographic(PTG) imaging materials are used as digital hardcopy imaging medium in diagnostic medical field. We obtained the hardcopy image by driving laser or thermal print head on PTG materials based on electronic data. Toners, as the most important of components to provide best image quality, is a compound added to modify the normally yellow-brown color of thermally generated Ag⁰ particles to black. In the paper, the effects of phthalic acid(H₂PA) and phthalazine(PHZ) as toners on photothermographic materials based on silver benzotriazole had been studied. The results indicated that H₂PA as a toner can promote development in higher pH of system and the promotion increased with the amount of H₂PA increased. We also found that the development of silver benzotriazole materials was promoted by the introduction of PHZ, and the promotion was strengthened by increasing the amounts of PHZ. The analysis data of SEM and IR indicated that a silver complex, which was supposed to be easy to transmit silver ions to development center to promote development, have been produced by introducing PHZ into the silver benzotriazole materials. The sharp of silver benzotriazole grains were changed by the silver complexes. The XRD data showed that the silver complexes had the same crystal structures as silver benzotriazole.