BN‐embedded oligomers with different pairs of BN units were synthesized by electrophilic borylation. Up to four pairs of BN units were incorporated in the large polycyclic aromatic hydrocarbons (PAHs). Their geometric, photophysical, electrochemical, and Lewis acidic properties were investigated by X‐ray crystallography, optical spectroscopy, and cyclic voltammetry. The B−N bonds show delocalized double‐bond characteristics and the conjugation can be extended through the trans‐orientated aromatic azaborine units. Calculations reveal the relatively lower aromaticity for the inner azaborine rings in the BN‐embedded PAH oligomers. The frontier orbitals of the longer oligomers are delocalized over the inner aromatic rings. Consequently, the inner moieties of the BN‐embedded PAH oligomers are more active than the outer parts. This is confirmed by a simple oxidation reaction, which has significant effects on the aromaticity and the intramolecular charge‐transfer interactions.

Quinoxaline-based cross-conjugated luminophores have been constructed and their charge transfer, piezofluorochromic, and sensing properties have been systematically investigated.

Electron-donating triphenylamine and/or electron-withdrawing pyromellitic diimide (PMDI) are functionalized on dithienylethene (DTE) and three novel photochromic materials have been designed and successfully synthesized. All the compounds display reversible photochromism due to the molecular switching between ring-closed isomers upon UV light irradiation and ring-open isomers upon exposure to visible light. Thus they can be applied as an anti-counterfeiting ink. Moreover, the study of the photoswitching kinetics reveals that both the ring-closing and ring-opening reactions are first-order reactions. Further charge population analysis discovers that the electron densities of the substituents at the DTE core have a dramatic influence on the photochromic properties. The incorporation of electron-donating triphenylamine groups at the α-position of the thiophene rings in the DTE unit facilitates the ring-closing reaction upon UV light irradiation. In contrast, the substitution of an electron-withdrawing PMDI unit in the DTE unit is beneficial to the ring-opening reaction upon irradiation of visible light. This work may help to understand the photochromism of DTE derivatives and provide a pathway for designing DTE-based photochromes with more or less sensitivity to UV or visible light.