The electrochemistry of boron doped diamond is currently an active field or research. In the majority of studies or diamond electrodes it has been reported that the material acts Lis a semi-metallic electrode. This paper is concerned with studies of moderately doped diamond electrodes in non-aqueous solvent. The results of Mott-Schottky analysis and the cyclic voltammetry of both ferrocene and bis(pentamethylcyclopentadienyl)iron are reported. The influence of surface bond termination, either hydrogen or oxygen. is also considered. It is shown that a response characteristic of a semiconductor can be attained Lit diamond electrodes immersed in acetonitrile provided that the redox couple does not have a similar energy to the graphitic surface states. The results obtained Lire discussed in terms of the Gerischer Marcus model of charge transfer at semiconductor electrodes.