Rearrangement reactions between Ln(MQ)3 and AE(MQ)2 (MQ = 8‐quinaldinolate) at 200–300 °C in a 1,2,4,5‐tetramethylbenzene (TMB) flux afforded the homoleptic heterobimetallic complexes [Ln2AE(MQ)8] (Ln = Eu, Gd, Tb, Er with AE = Mg; Ln = La, Eu with AE = Ca) and [Eu3Ba(MQ)11]·2TMB. From an attempt to prepare [La2Mg(MQ)8], [Mg4(MQ)8] was isolated, and it was also obtained with the heterobimetallics from syntheses in which Ln = Eu, Gd, Tb. Surprisingly, [Er3(MQ)7CO3] was isolated from an attempted synthesis of [Er2Ca(MQ)8], and the Eu analogue was prepared from Eu(MQ)3 and CaCO3 in TMB at 210 °C. The [Ln2AE(MQ)8] complexes have a trinuclear structure with a linear or nearly linear Ln–AE–Ln array. Octacoordinate Ln atoms have one terminal chelating (N, O) MQ ligand and three chelating‐bridging MQ ligands that link to AE through the phenolic oxygen atoms, leading to hexacoordination of AE. In [Eu3Ba(MQ)11]·2TMB, an Eu atom is positioned above the Ba–Eu vector of a somewhat bent Eu–Ba–Eu unit. All atoms are octacoordinate, and the structure features μ3‐η2(N,O):η1(O):η1(O) MQ ligands in addition to terminal chelating and chelating‐bridging μ‐η2(N,O):η1(O) MQ groups observed in [Ln2AE(MQ)8] complexes. The three modes of ligation are also observed in [Mg4(MQ)8] where Mg is hexacoordinate but with two different arrays. [Ln3(MQ)7CO3] complexes have a perpendicular Ln–Ln–Ln arrangement with two octacoordinate metal atoms flanking a heptacoordinate one. Carbonate binding features the new η1(O)‐μ3‐η1(O′):η1(O′):η1(O′)‐η1(O″) ligation mode. The carbonate ligand chelates to each of the outer Ln atoms, which are also linked to one chelating and two chelating‐bridging MQ ligands. Attached to the central Ln atom is a carbonate oxygen atom, four oxygen atoms from chelating‐bridging MQ ligands and a terminal MQ chelate.