Biaryls and heterobiaryls are an important class of aromatic and heterocyclic compounds due to their diverse presence in natural products, pharmaceuticals, agrochems., ligands, polymers and organic materials. A new heterogeneous catalytic diazotization and subsequent coupling of diazonium salts with aromatics hydrocarbons and heterocycles for the synthesis of biaryls and heterobiaryls has been developed. This reaction involves in situ K-10 montmorillonite-catalyzed diazotization and subsequent C-C bond formation by the nucleophiles. The establishment and optimization of the approach for the direct synthesis of biaryls and heterobiaryls will be discussed. The synthetic route features the activity of diazonium salt at high temperature which becomes a partial C-electrophile and upon the nucleophilic attack a N2 mol. leaves the system and a C-C bond is formed. Thus, the reaction is suggested to be of Friedel-Crafts nature from the nucleophile's point of view. This synthetic route provides a wide substrate scope with high yields and selectivities. As in this reaction no harmful products are generated, catalyst is recyclable and product isolation entails simple extraction and evaporation, this method also comply with green chem. principles. The widespread industrial (pharmaceuticals, agrochems., and materials) interest in the target compounds this new process could significantly decrease the environmental impact of traditional syntheses of biaryls and heterobiaryls.