Highly ordered smectic structures of disc–rod luminescent liquid crystals: the role of the tolane group

Two novel calamitic tolane luminogen-modified triphenylene-based discotic luminescent liquid-crystals (LLC) were rationally designed and synthesized to investigate the self-assembly competition between triphenylene discogens and tolane calamitic mesogens. The results show that the LLCs formed thermodynamically stable highly ordered smectic B or smectic E phase as well as lamellar crystal structures, instead of the traditional columnar phase. The photoluminescence properties, which changed according to crystal structures, were also studied, indicating the important role of the tolane group in manipulating the self-organization of disc–rod molecules and consequently achieving enhanced emission.