A novel chalconyl homologous series of liquid crystalline derivatives RO -C6H4-COO - C6H4-CO - CH=CH - C6H4– OC4H9 (n) (para) have been synthesized and studied with view to correlate the liquid crystal (LC) behavioral properties and the molecular structure of a substance. Present novel series consisted of thirteen homologue members (C1 to C18) whose, only nematogenic mesomorphism commences from C5 homologue and continued up to C18 homologue in enantiotropic manner with absence of smectogenic character. Transition temperatures and textures of nematic phase were determined using an optical polarizing microscopy equipped with a heating stage (POM). Transition curve Cr-N/I behaved in normal manner. Textures of the nematic phase are threaded or schlieren. Analytical and spectral data supported molecular structures of homologues. Thermal stability for nematic is 118.22 C° and the degree of mesomorphism vary from 10.0°C to 36.0°C at the C18 and C6 homologue respectively. It is a middle ordered melting type series, whose relative group efficiency order for nematic derived.