Detonation nanodiamond possesses facile surface functional groups and can be chemically processed for many engineering applications. In this work, we demonstrate the functionalization of nanoscale diamond particles with aryl organics using Suzuki coupling reactions. In route one, hydrogenated nanodiamond is derivatized with aryl diazonium to form the bromophenyl-nanodiamond complex, this is subsequently reacted with phenyl boronic acid to generate the biphenyl adduct. In route two, the nanodiamond is first derivatized with boronic acid groups to form the boronic acid-nanodiamond complex, this is followed by Suzuki cross coupling with arenediazonium tetrafluroborate salts to generate the biphenyl product. Good chemoselectivity can be obtained in both routes. The efficiencies of the Suzuki coupling reaction can be further improved by performing the chemistry in a microreactor where electro-osmotic flow accelerates the mixing of reactants. Using the Suzuki coupling reactions, we can functionalize nanodiamond with trifluoroaryls and increase the solubilities of nanodiamond in ethanol and hexane. Fluorescent nanodiamond can be generated by the Suzuki coupling of pyrene to nanodiamond.