We have designed, synthesized, and evaluated the physical properties of some high birefringence (Delta n) isothiocyanato phenyl-tolane liquid crystals. These compounds exhibit a Delta n similar or equal to 0.48-0.52 at room temperature and wavelength lambda =633nm. Laterally substituted short alkyl chains and fluorine atom both eliminate smectic phase formation and lower the melting temperature. Both the moderate melting temperature and very high clearing temperature make those compounds attractive for eutectic mixture formulation. Examples of the mixtures containing the described components are presented.