Photo- and electro-luminescent properties of thermotropic liquid crystalline quaterphenyl analogues comprising a 2,2 '-bi-1,3,4-thiadiazole unit

Thermotropic liquid crystalline quaterphenyl analogues constituting a centr al 2,2'-bi-1,3,4-thiadiazole ring, the compounds 5,5'-bis(4-methoxy-and4-oc tyloxy-phenyl)-1, 3, 4-thiadiazole, have been prepared and their photolumin escent (PL) and electroluminescent (EL) properties evaluated. The materials form enantiotropic smectic and nematic phases. The PL spectra showed that they emit blue and green fluorescence in the solid state. The octyloxy comp ound exhibited an EL spectrum with blue emission and is a candidate for org anic EL applications.