The analysis of element distributions in polymer-based structures using IBA techniques offers the possibility to study a variety of interesting problems, in particular diffusion and reaction phenomena. Indium diffusion in model polymer light emitting diodes (p-LEDs) consisting of a stack Al/poly-(phenylenevinylene)/indium-tin-oxide/glass has been studied with Rutherford backscattering spectrometry (RBS), particle induced X-ray emission (PIXE), X-ray photoelectron spectroscopy (XPS), and low energy ion scattering (LEIS). A second example is provided by the analysis of organic optical gratings, in which the diffusion of labeled monomers during holographic photo-polymerization of photo-reactive monomer mixtures has been studied with μPIXE using a scanning proton microprobe. Since polymers are sensitive to ion irradiation, a new RBS/ERDA set-up has been constructed that is equipped with a sample holder mounted on a closed cycle helium refrigerator, which enables the cooling of samples to cryogenic temperature...