Benzophenone-containing, anhydride-terminated hyperbranched poly-(amic acid)s were end-capped by ortho-alkyl aniline in situ and then chemically imidized, yielding autophotosensitive hyperbranched polyimides. The polyimides were soluble in strong polar solvents, such as N-methyl-2-pyrrolidone, N-dimethylformamide, dimethylacetamide, and dimethyl sulfoxide. Thermogravimetric analysis revealed their excellent thermal stability, with a 5 wt % thermal loss temperature in the range of 527-548 degreesC and a 10 wt % thermal loss temperature in the range of 562-583 degreesC. The strong absorption of the polyimide films in ultraviolet-visible spectra at 365 nm indicated that the hyperbranched polyimides were patternable. Highly resolved images with a line width of 6 mum were developed by ultraviolet exposure of the polymer films. A well-defined image with lines as thin as 3 mum was also patterned, but the lines were rounded at the edges. (C) 2003 Wiley Periodicals, Inc.