A major difficulty in studying the physical properties of molecular complexes is their temperature. Complexes are either thermally unstable or have sufficient motion as to make it very hard to assign structure from measurements of their spectra. A very recent development in physical sciences is the use of helium droplets to trap and cool complexes. With a temperature of just 0.38 K above absolute zero, droplets are capable of trapping unstable species and reducing their temperature, which makes analysis of their spectra comparatively simple. In this study we propose to use this approach to investigate complexes between transition metals and benzene, which are seen as models for metal / pi electron interactions at metallic surfaces. Cooling the complexes to 0.38 K will make it possible to identify the nature of the electronic transitions taking place and to use these transitions to establish the magnetic moment of the complex. A combination of laser vaporization and the cold helium droplets will make it possible to study a wide range of otherwise unstable metal/benzene complexes.