Two pairs of calamitic liquid crystalline molecules, (+)-2-[4′-(S)-sec-butoxyphenyl]-5-(4′-hexoxyphenyl)toluene () and (+)-2-(4′-hexoxyphenyl)-5-[4′-(S)-sec-butoxyphenyl]toluene (), (−)-2-[4′-(R)-sec-butoxyphenyl]-5-(4′-hexoxyphenyl)toluene () and (−)-2-(4′-hexoxyphenyl)-5-[4′-(R)-sec-butoxyphenyl]toluene (), have been designed and synthesized. Each of the molecules consists of a p-terphenyl core substituted with a methyl group on the middle ring, a chiral sec-butoxy tail, and an achiral n-hexoxy tail. The geometrical difference between () and () lies only in the location of the methyl group on the effective mesogenic core. Yet, such a small change in the structure gives rise to remarkable differences in mesogenic properties and handedness. Both and have an enantiotropic cholesteric phase (N*) and a monotropic twist grain boundary C* phase (TGBC*), whereas and exhibit only a monotropic N* phase. Moreover, () and () have opposite handedness in the N* phase, and and even have a helical inversion from N* to TGBC* phase through a non-helical chiral mesophase. Chirality, 2011. © 2011 Wiley Periodicals, Inc.