High molecular weight soluble polyphenyl-as-triazines were prepared at ambient temperature in m-cresol by the cyclopolycondensation of 2,6-pyridinediyl dihydrazidine (diamidrazone) with various aromatic dibenzil type reactants. Clear lemon yellow films, which exhibited good toughness and flexibility, were cast from solution. The isolated yellow polymers readily formed clear yellow to orange solutions in chloroform or sym-tetrachloroethane at concentrations as high as 30% solids. By TGA, polyphenyl-as-triazines exhibited a two-stage decomposition, commencing at ∼400°C, in both air and nitrogen. The polymers exhibited excellent stability at 260°C (500°F) in air, but at 290°C (554°F) significant weight losses occurred. Initial evaluation as an adhesive and resin matrix in Morganite I composites demonstrated the potential of polyphenyl-as-triazines as structural resins. Prior to polymer work, a series of model compounds were prepared and characterized.