B4PymPm is an isomer to B2PymPm and B3PymPm. It has a 2-methylpyrimidine core structure with four pyridine pendants. It is electron-deficient and can be used in OLEDs and photovoltaics (e.g. perovskite solar cells) as an electron-transporting or hole-blocking layer material.
Due to its intermolecular hydrogen bonding, B4PymPm molecules self-assemble in a horizontal orientation - parallel to the substrate, with a significantly large anisotropy. This self-assembly gives high molecular stacking in films with high π-orbital overlaps, which can significantly enhance charge-carrier mobility and transport.
HOMO = −7.3 eV
LUMO = −3.7 eV [6]