A novel chalconyl liquid crystalline (LC) homologous series with two phenyl rings and one central bridge RO-C6H4-CH=CH-CO-C6H4(O-C18H37) (meta) has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on thermotropic LC behaviors or properties. Homologous series of present investigation (C-1-C-18) consists of thirteen homologues, and thermotropic mesomorphism for nematic and smectic commences from C-3 and C-6 homologues respectively. The C-3, C-4, and C-5 homologues are enantiotropically nematic, whereas, the homologues from C-6 to C-18 are monotropically smectic plus nematic. Melting points and transition temperatures were determined using a polarizing optical microscope (POM) equipped with a heating stage. The textures of the nematic phase are threaded or Schlieren and that of a smectic phase are fan shaped of smectic-A or smectic-C type. The Cr-I/M, N-I/I-N, and N-Sm transition curves behave in the normal manner, and the Cr-I/M exhibits an odd-even effect. Analytical, thermal, and spectral data confirm the molecular structures. Thermal stabilities of smectic and nematic are low. Mesophase lengths are very short, ranging between 1-8 degrees C and 14 degrees C. The novel compounds are compared with a known series.