A model of a mesogenic molecule, built up as a rigid anisotropic Gay-Berne site mimicking the aromatic core, connected to an array of isotropic sites mimicking a flexible chain, is proposed and tested in molecular dynamics calculations. Simulations have been performed on a system composed of 256 molecules with three different numbers of methylenic units in the chain, in order to explore the effect of chain length on static and dynamic properties. The systems are all at the same mass density and temperature and result in nematic liquid crystalline phases. The order parameters for various molecular fragments and the T-1z nuclear magnetic resonance (NMR) relaxation times of deuterons are in agreement with previous molecular dynamics simulations on atomistic systems and, at least qualitatively, with H-2-NMR experimental results. The intermolecular interactions are always dominated by the anisotropic site simulating the molecular core. The influence of the phase order on the chain static and dynamic properties is put in evidence. Extensions of the model are suggested in order to have a better reproduction of the dynamical features of such systems.