While organic phase structure has long been linked to its phase behavior, we recently proposed that organic phase structure over a wide range of binary extractant/diluent mixtures is consistent with critical fluctuations originating from the critical point associated with the third phase formation phase transition. This could explain certain limitations to common microemulsion descriptions of LLE systems, such as the presence of structure in the organic phase even in the absence of extracted polar solutes needed to induce the formation of water-in-oil aggregates. Our recent studies find that the fluctuations in many-component organic phases contain-ing extracted acid, water and metal salts are quantitatively consistent with the theory of critical phenomena. In particular, the scattering obeys an Ornstein-Zernike relation typical of critical fluctuations, with divergent behavior as the critical temperature for phase separation is approached that agrees with predictions for the 3D Ising model. Since this universality class of phase transitions includes binary fluid mixtures, this indicates that pseudobinary critical fluctuations develop along a single compositional degree of freedom. This suggests that the theory of critical phenomena may provide a deep, quantitative connection between structure and phase behavior in LLE that can be meaningfully explored through simplified organic phases. To test this applicability of simplified organic phases to complex, realistic LLE organic phases, we investigate critical scaling through temperature dependence of organic phase structure in binary extractant/diluent mixtures, which allows us to compare critical behavior to more complex organic phases. We look to see if well-known relationships between extractant and diluent alkyl chain lengths and their impact on promoting or inhibiting third phase formation 44,65-68 can be reproduced in these simplified systems. If this were the case, it might suggest that screening of compatible extractant/diluent combinations can be conducted in simplified systems that are easier to study experimentally and computationally.