Boron-doped polycrystalline diamond thin films were grown over POGO graphite by a microwave plasma assisted chemical vapor deposition (CVD) using a gas mixture of methane and hydrogen. As-deposited films were analyzed by scanning electron microscopy (SEM) for their morphology. Cyclic voltammetry has been used to evaluate the background current response corrected for the uncompensated IR drop. Redox kinetics of ferri-ferrocyanide at the boron-doped diamond/graphite electrode has been investigated. The lowest observed peak separation was observed to be 222 mV at a scan rate of 5 mV/s. The heterogeneous electron transfer rate constant has been determined using the experimental data and a COOL algorithm. The rate constant was found to be similar to 2 x 10(-4) (alpha = 0.5 or variable) cm/s, and subsequently, the reaction kinetics was considered to be sluggish at the diamond electrode/solution interface. The diamond films grown over graphite electrode material may have uses in electrosynthesis and electroanalysis since the doped diamond films an electrically conductive and chemically inert.