A detailed study has been made concerning the metalation of benzene and ferrocene by means of n-butyllithium + N,N,N′,N′-tetramethylethylenediamine in hexane and ethyl ether solution. Optimum conditions are described for the formation of phenyllithium and 1,1′-ferrocenylenedilithium, and the utility of these reagents inorganic and organometallic syntheses is demonstrated by their conversion in good yield to a variety of products. The n-butyllithium—diamine complex in hexane has been shown to metalate the methyl group of methyldiphenylphosphine in 54% yield.