A series of new polyhydrazides has been synthesized via direct polycondensation of benzofuro[2,3-b]benzofuran-2,9-dicarboxylic acid (BBDA) with dihydrazides in ionic liquids (ILs) as a new class of solvents, which have interesting properties, such as nonvolatility, high ionic concentration, good thermal stability, and nonflammability. Direct polycondensation is successfully proceeded in ILs and triphenyl phosphite (condensing agent) without any additional extra components, such as LiCl and pyridine, using in similar reactions in ordinary (IL can act as both solvent and catalyst). The polyhydrazides have been obtained in quantitative yield and their intrinsic viscosities ranged from 0.21 to 0.47 dL g(-1). The polyhydrazides were characterized by means of IR, H-1-NMR, inherent viscosity (eta(inh)), solubility test, TGA, DSC, CHN analysis, and ultraviolet lambda(max), They could be thermally converted into the corresponding poly(1,3,4-oxadiazole)s approximately in the region of 210-330 degrees C, as evidenced by the TGA thermograms. The polymers were readily Soluble in several organic polar solvents, such as DMAc, N,N-dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone and could be cast into flexible films. The polymer were metallized via complexation with various transition metal. The complexes were investigated by X-ray diffraction, IR, and UV spectrophotometry. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113:1935-1944,2009