text: Boron porphyrins are a variety of porphyrin, a common macrocycle used for photosensitization and metal trapping applications, that incorporate boron. The central four nitrogen atoms in a porphyrin macrocycle form a unique molecular pocket which is known to accommodate transition metals of various sizes and oxidation states. Due to the diversity of binding modes available to porphyrin, there is a growing interest in introducing other elements (i.e. main group elements) into this pocket.
  Boron in particular has been shown to prefer binding to porphyrin in a 2:1 stoichiometry, primarily due to its small atomic radius, but the Group XIII element will bind in a 1:1 ratio with corrole, a macromolecule with a structure similar to porphyrin but with a smaller N pocket.
  Boron porphyrins are of interest because of the unique geometric environment to which both boron and porphyrin are subjected upon B-N  bond formation. These new geometric motifs lead to novel reactivity, one of the most surprising examples being sterically-induced reductive coupling. Possible applications for boron porphyrins include BNCT delivery agents and OLED devices.
  Also of interest are molecules containing both boron and porphyrin moieties, but without B-N bonds. Examples include diketonate-porphyrin compounds and dyads (two-component molecules) containing the classic BODIPY dye.