Double swallow-tailed compounds are special cases of tetra-catenar mes
ogens (mesogens consisting of a rod-like core and two half-disc shaped
moieties), where the branches are not attached directly to the termin
al rings. Experiments are reported in which the middle part of the cor
e and the length of the terminal chains were varied. The resulting eff
ects on the transition temperatures and phase behavior are described a
nd trends pointed out.