Transition-metal-catalyzed N-H insertion of a diazocarbonyl compound is applied for polycondensation for the first time to give a new type of aromatic polyamine. The well-defined polyamines were obtained by [RuCl2(p-cymene)](2)-catalyzed reaction of diethyl1,4-phenylenebis(diazoacetate) with dianilines bearing a variety of linkers between two aniline units. The polycondensation proceeded at 30 degrees C in CH2Cl2 with 5.0 mol % of the Ru metal to [NH2 or N-2 = C] to afford the products with M-n = 6400-28 300 in moderate to high yield. Ethoxycarbonyl groups located at an adjacent position to NH imparted solubility to the polyamines, and their glass transition temperatures can be varied depending on the linker structure in a range of 88-173 degrees C.