Mixts. of Mo2(O2C(CH2)nCH3)4, where n = 6 (=Oct) and 7 (=Non), form a columnar mesophase upon heating and the crystal-to-liq. crystal phase transition temps. differ little from those predicted by the Shroder-van Laar equation for an ideal mixt. The XRD of the solid sample obtained from cooling a 1:1 mixt. of Mo2(Oct)4 and Mo2(Non)4 conformed to a triclinic cell with lattice parameters intermediate between those of the pure compds. Similarly in the mesophase the intercolumnar sepn. (d) was an intermediate distance. The phase behavior of mixts. of Mo2(non)4 and Mo2(O2C(CH2)10CH3)4 [Mo2(Dod)4] were more complex, but in all instances a mesophase was obsd. whereas that of the pure Mo2(Dod)4 shows only a cryst. solid to isotropic phase transition. Mixts. of Mo2(Oct)4 and Mo2(O2C(CF2)6CF3)4 [Mo2(Octf)4] also form a columnar mesophase with an intercolumnar sepn. intermediate between that of the pure compds. The mesophase is an optically pos. material with the largest component of the index of refraction coincident with the columnar axis. The solid to mesophase transition temps. varied significantly from that predicted for an ideal mixt. These results are discussed from facile carboxylate scrambling to produce Mo2(O2CR)4-n(O2CR')n, where n = 0-4 in both the mesophase and the resultant solid soln. [on SciFinder(R)]