Styrene on Si(111)-7 × 7 surfaces was investigated as a model molecular electronics system to study the effects of conjugation to the semiconductor surface. Scanning tunneling microscopy imaging, combined with theoretical images show that styrene molecules bind in a [4 + 2] cycloaddition mode, binding at the terminal C of the vinyl substituent and a C on the phenyl ring. These single molecule results are consistent with those of ensembles of molecules as obtained by high resolution electron energy loss spectroscopy. For styrene on Si(111)-7 × 7, the aromaticity of the phenyl ring is broken and the conjugated π-system does not extend to the silicon surface, potentially hindering conduction between molecule and surface. However, styrene does retain a conjugated π-system after binding, as is evident in the π-π* shakeup transition in the C 1s x-ray photoelectron spectra as well as UV photoemission spectra. This suggests that styrene-type molecules, when bonded to Si surfaces, do not maintain ready conduction between molecule and surface.