Here we investigate the behaviour of these quantities at I - N and N - N coexistence. We have chosen S$_{tot}$ to be a simple weighted average of the S$_{i}$ . As such, each particle contributes to S$_{tot}$ independently of its size. Of course there are other suitable choices which may be appropriate to certain applications; the S$_{i}$ in the sum for the total order may be weighted by the surface area of the platelet, for example. Due to the absence of particles of species 2 at x = 0, S$_{tot}$ and S$_{1}$ take the same value. Similarly at x = 1, S$_{tot}$ and S$_{2}$ take the same value. As x increases from 0 to 1, S$_{tot}$ changes smoothly. In Fig. 1d the FMT values for S$_{1}$ , S$_{2}$ and S$_{tot}$ are smaller than those obtained from Onsager theory, which places the values much higher. However FMT predicts that the difference between S$_{1}$ and S$_{2}$ to be bigger than Onsager theory does. S$_{tot}$ at x = 0 takes the same value S$_{tot}$ = 0 . 531 as previous work (and agrees well with simulation [25]) in the monodisperse case and the the order parameters vary smoothly in the same manner as for Onsager theory. In Fig. 2 we show the results for λ = 1 . 4. There is a widening of the biphasic region between the two pure components, clearly seen in Fig. 2a where we show the phase diagram in the ( x, c ) representation. FMT again predicts that the mixture undergoes I - N phase separation at lower densities than Onsager theory. The tie lines become less steep with a smaller positive gradient than for λ = 1 . 1 for intermediate values of composition indicating that there is larger difference in mole fraction between coexisting isotropic and nematic states. The widening of the biphasic gap is even more noticeable in the ( c$_{1}$, c$_{2}$ ) representation (Fig. 2b), especially for the case of Onsager theory. In the ( x, p ∗ ) representation (Fig. 2c), the spinodal again lies above the nematic binodal for Onsager theory. However, for FMT we see that while the spinodal is above the nematic branch of the binodal close to x = 0 and x = 1 the curve enters the biphasic region in between about x = 0 . 1 and x = 0 . 6. S$_{1}$ is smaller than S$_{2}$ and their difference has increased for both theories, with FMT still possessing the larger difference suggesting that the particles of species 2 are significantly more ordered than species 1 for a given mole fraction at coexistence. In Fig. 3 we plot the graphs for λ = 1 . 7. The I - N biphasic gap becomes even more pronounced. The results for FMT (Fig. 3a) show that tracing along the nematic branch of the binodal as x increases leads to an increase in c . At approximately x = 0 . 2, c then decreases and near x = 0 . 6 bends back on itself before approaching x = 1. This bending of the binodal constitutes a re-entrant phenomenon. There is also a large range of compositions between about x = 0 . 1 and x = 0 . 6 for which the biphasic I - N phase overlaps for both 18