•Four asymmetrical heterotwistacenes were synthesized.•X-ray analysis exhibits the formed molecules have twisted structures.•The photodetector devices were fabricated to test their performance.Four novel pyrene-fused asymmetrical twistacenes (1–4) containing heteroatoms in the main frameworks were synthesized and their structures are characterized by using 1HNMR, 13C NMR and mass spectrometry. Single crystal X-ray analysis shows that compound 1 has a twisted structure with the torsion angle of 26.39° between pyrene moiety and naphthalene unit, and the terminal benzenedithiol group fold out of the naphthalene plane with dihedral angle of 53.10°. Moreover, the effect of heteroatoms on their optical and electrochemical property was studied in detail. The fabricated devices based on 3 and 4 can produce steady photocurrent upon irradiation of a halogen lamp.

Five novel organic conjugated derivatives containing multifraction twisted acene units have been synthesized and characterized. These compounds and the model molecule 2-methyl-5,12-diphenyl-6:7,10:11-bisbenzotetracene emit strong blue light in diluted solution with quantum yields of 0.21–0.67, while in the solid state, except for the 1,2,3,4,5,6-hexa(2-(5,12-diphenyl-6:7,10:11-bis(4′-tert-butylbenzo)tetracene))benzene, green luminance is seen. The experimental results also indicate that the multifraction structure leads to a significant fluorescence enhancement (over two times) compared to the monomer, which might be attributed to the formation of delocalized excited state in multibranch structures. The quantum-chemical calculation implies that only two branches are involved in formation of the delocalized system for the multibranched derivatives. Furthermore, the organic light-emitting diode (OLED) devices using compounds 1,4-di(2-(5,12-diphenyl-6:7,10:11-bis(4′-tert-butylbenzo)tetracene))benzene, 1,3-di(2-(5,12-diphenyl-6:7,10:11-bis(4′-tert-butylbenzo)tetracene))benzene, and 1,3,5-tri(2-(5,12-diphenyl-6:7,10:11-bis(4′-tert-butylbenzo)tetracene))benzene as emitters exhibit good electroluminescent performance. Our systematic studies might provide more chances to challenge the rational design and synthesis of new- and high-generation branched dendrimers.Keywords: acene; emitter; OLED; physical property; synthesis; twisted structure;