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p-n-alkoxycinnamoyl cholrides when treated with p- hydroxyacetophenone yield a homologous series ofmesogens. The first member is a monotropic nematogen; exhibition of enantiotropic nematic mesophase begins from the second memeber and persists up to the butyl derivative. Both smectic and nematic mesophases are exhibited by the pentyl and hexyl derivatives. The homologues rom heptyl to octadecyl exhibit smectic phase only. the usual odd-even effect is well displyed. Nematic-isotropic treansition curves for both even and odd memebers showf an initial slight slump up to the heptyl derivative; the smectic-isotropic transition curve shows a rising tendency followed by a slight downward slope towards the highest member. The homologous series is thermally very stablef and exhibits a wide mesomorphic range. The thermal stabilities and other characteristics are discussed.

Twelve new mesomorphs belonging to the homologous series of mesogens: p-(p'-n-alkoxycinnamoyloxy)benzal p"-phenetidines have been synthesized. This is a high melting homologous series of mesomorphs. The first four members decompose at very high temperatures; the pentyl, hexyl and heptyl derivatives exhibit enantiotropic nematic threaded texture. Polymesomorphism commences from the eighth member and continues up to the last viz. octadecyl derivative. The smectic phase shows focal conic fan shaped texture of the smectic A variety. The usual odd-even effect is observed in the case of nematic-isotropic transitions. The smectic-nematic transition curve rises steeply as the series is ascended increasing the smectic range at the cost of the nematic mesophase. The mesomorphic phases offer wide ranges and the thermal stabilities are as per the molecular geometry and the substituents responsible for the overall molecular forces.