The orientational ordering of six liquid crystalline compounds in two homologous series, namely 4-n-alkoxybenzilidene-4’-n-alkylanilines (nO.m) and 4,4’-di-n-alkyldiphenyldiacetylenes (PTTP), has been studied at different temperatures by 2D C-13 NMR with variable angle sample spinning. The carbon-proton dipolar coupling constants were obtained and the order parameters of the aromatic cores were calculated. The C-13 chemical shifts for each carbon nucleus in the aromatic cores were also measured as a function of temperature by 1D C-13 NMR. A linear correlation between the chemical shifts and the order parameters was observed for each homologous series. The results furnish a useful and convenient database for the evaluation of order parameters for these two series of liquid crystals from simple measurements of C-13 chemical shifts.