Both simulated systems evolved to form a smectic A phase. The evolution of the orientational order parameters P2 and P4, obtained using the N-O vector as the principal axis, are shown in Figure . The evolution of the translational order parameter τ and associated layer spacing d, obtained using the C4′ biphenyl carbon atom to define the molecular position, are shown in Figure . An analysis of the angle between the director and the layer normal, presented in the SI, confirmed that both simulated systems formed a smectic A phase. The simulated smectic A phase of 8OCB formed relatively quickly (ca. 60 ns) but was typically not stable (beyond ca. 200 ns), whereas that of 9 formed more slowly (ca. 200 ns) and was more stable (to at least 1000 ns). We attribute the behaviour of 8OCB to the ready formation of diffuse layers in a simulation that lacks long-term stability due to the use of anisotropic pressure coupling, which allows the simulation box aspect ratios to vary and avoids bias from a constrained box shape but which results in an unstable simulation box and phase for this system. By contrast, we attribute the behaviour of 9 to the bulky endgroup leading to the slower formation of more ordered layers that give a more stable simulation once formed. In comparison with the respective experimental data at the relevant temperature, these simulated phases give average P2 values that are closely similar, average P4 values that are slightly higher, and average d values that are closely similar. We do not have experimental data for a comparison with the average τ values, but together the available comparisons suggest that the simulations may reasonably be used as an aid to interpret the experimental data.