Inexpensive synthesis of diamine, 1,4-bis(4-nitrophenoxy)-2-(6-oxido-6H-dibenz < c,e > < 1,2 > oxaphosphorin-6-yl) phenylene was revealed in this work. Based on the diamine, a series of organosoluble polyamides were prepared by direct polycondensation of the diamine with various aromatic diacids using triphenyl phosphite and pyridine as condensing agents. The number-average molecular weights of the resulting polyamides range from 4.2 x 10(4) to 10.5 x 10(4) g/mol, and the weight-average molecular weights are in the range of 7.5-28.2 x 10(4) g/mol. The T(g)s of these polyamides range from 210 to 255 degrees C by dynamic mechanical analysis. The resulting polyamides are tough and flexible with tensile strength, elongation at break and moduli range from 84 to 101 MPa, 4.8-7.0%, and 2.36-3.22 GPa, respectively. The degradation temperatures (T-d 5%) and char yields at 800 degrees C in nitrogen range from 460 to 486 degrees C and 59-68 wt%, respectively. The cutoff wavelength of these polyamides falls in the range of 345-366 nm, showing a very light color characteristic. In addition, these polyamides display good oxygen plasma resistance. (C) 2009 Elsevier Ltd. All rights reserved.