A review. Strategies to functionalize simple, though structurally challenging, compds. in regiodivergent manner are outlined. The starting materials are inexpensive (5-500 e/mol) arenes or heterocycles bearing heterosubstituents such as Cl, F, CF3, OCF3, and OMe. A metal is introduced at the targeted position either by direct hydrogen/metal exchange or, if this is not feasible, by use of organometallic precursor species as relay stations. The derivs. thus produced are versatile intermediates that may be employed as building blocks for further elaboration or even as scaffolds in combinatorial synthesis. [on SciFinder (R)]