Borylated molecules and polymers are of great interest due to their broad application in organic synthesis and materials science. The functionalisation of organic substrates with boryl groups R2B is based on classical synthetic methods e.g. hydro- and diboration of C-C multiple bonds. Likewise, borylenes B-R should be versatile reagents for corresponding functionalisations, however, the chemistry of such species remained unexplored due to their high instability.Pioneering work in our laboratories has proven that complexes of the type [LxM=B-R] not only stabilise elusive borylenes B-R in the coordination sphere of various transition metals but, more importantly, serve as unprecedented sources for these species under ambient conditions in condensed phase. Thus, the major objective of the current proposal is to establish novel reactivity patterns based on B-R fragments for the functionalisation of organometallic and organic substrates. Particular attention will be paid to the synthesis of novel molecular and polymeric species with significant potential as materials. Given the pronounced importance of boron containing species in organic synthesis, catalysis and materials science, the proposed project is expected to have a significant impact on these areas of applied molecular science. In addition, a wide range of fundamental aspects will be covered, targeting e.g. novel conjugated cyclic systems or molecules with unprecedented boron-element combinations.The following subjects will be pursued:1)Cationic and anionic dimetalloborylenes as complementary building blocks in synthesis2)Application of borylene metathesis in stoichiometric and catalytic transformations3)Borylene transfer for organometallic synthesis and borylene based pi-conjugated materials