To improve the optical transparency and organosolubility of aromatic polyimides derived from 4,4'-oxydianiline (4,4'-ODA), two new aromatic diamines, 2,2'-diiodo-4,4'-oxydianiline (DI-ODA) and 2,2'-bis[(p-trifluoromethyl) phenyl]-4,4'-oxydianiline (BTFP-ODA) were synthesized by using 4,4'-ODA as a starting material. Novel polyimides were prepared from these two diamines with various commercially available aromatic dianhydrides via a one-step high-temperature polycondensation procedure. Most of these polyimides showed enhanced solubility in common organic solvents compared with those corresponding polyimides derived from 4,4'-ODA. Especially, polyimide derived from BTFP-ODA and rigid pyromellitic dianhydride (PMDA) was also soluble in DMF, DMAc, DMSO, NMP, and m-cresol at room temperature. These polyimides had inherent viscosities from 0.41 to 1.26 dLg (1) in NMP or m-cresol at 30 degrees C. Transparent, flexible, and tough films can be obtained by casting from their DMAc or m-cresol solutions. These films had the UV onset wavelengths in the range of 347-391 nm and the wavelengths at 80% transmission of 445-544 nm, indicating high optical transparency. They also exhibited good thermal stability with glass transition temperatures in the range of 260-327 degrees C. The decomposition temperatures of these polyimides at 5% weight loss under nitrogen were 429-609 degrees C. Because of the weak carbon-iodine bond, polyimides derived from DI-ODA decomposed at lower temperatures than polyimides derived from BTFP-ODA. The effects of the substituents at the 2 and 20 positions of 4,4'-ODA on the properties of polyimides are also discussed. High optical transparency and good solubility combined with high thermal stability make these polyimides potential candidates for soft electronics applications. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 120: 3159-3170, 2011