Spectroscopic and DFT investigations: Mesogenic alpha-Naphthyl derivatives with central cinnamate and ester linkages

•New naphthalene derivatives with central cinnamates and ester groups were synthesized and characterized.•Effect of varying terminal chain on mesomorphism was studied.•Steric effect of the terminal naphthalene moiety was studied using MM2 model.•Studied the polarization, interaction energy, HOMO – LUMO orbital energy gap using (TD-DFT) at the B3LYP/6- 31 g (d,p) level of theory.•TD-DFT calculations using Gaussian09 were also used to explain the UV data by calculating excitation wavelength for the series i and series II member (n = 1).