Ever since the discovery of the conducting properties of halogen doped polyacetylene in 1977, electronic devices comprised of organic materials have become a hot research topic. The challenges remaining for the potential of organic electronics to come to full fruition lie in the characterisation and control of effects occurring at small scales, where interface effects start to play dominating roles. In this thesis the effects of dosing films consisting of the two organic molecules sexithiophene (6T) and sexiphenyl (6P) on the inorganic substrate Cu(110) with bromine was investigated. When dosing 6P films with bromine at RT, increases in the work function of the sample were observed. These increases occurred concomitantly with the shift of the highest occupied molecular orbital (HOMO) and HOMO-1 features of the molecular films as observed with UPS. Although the intensity in the HOMO and HOMO-1 region also subsided substantially, emptying of these orbitals across the entire thickness of the film could not be unambiguously concluded. Here the RDS technique brought some clarity as firstly, redshifting of the entire spectrum was observed upon bromine dosing at RT, and secondly after flashing the film to 150 ?, the clear formation of gap-states was visible, indicative of charge transfer. Importantly, the comparatively low RD intensity of the observed gap-states supports the conclusion that the molecular film is in fact being doped by the bromine, albeit only up to the first two layers. A similar verdict was reached for the studied 6T films, where evidence of gap states in the RD spectra was observed only after flashing the films. However, the plethora of optical transitions observed after letting the bromine dosed samples rest unperturbed for several days was strongly indicative of additional parasitic processes taking place along with any charge transfer effects.