Heterometallic 3d-4f-carboxylates containing transition metal as a part of organometallic moiety represent a poorly studied class of compounds despite their intriguing properties: the ability to combine specific properties of the organometallic part and REE ion and their potential to be molecular precursors for mixed-oxide functional materials. Until recently mostly ferrocene derivatives were known (see references in [1,2]). Lately we synthesized and studied 3d-4f-carboxylates containing cerium group lanthanides, cymantrenyl moiety and THF [1] or DMSO [2] as neutral ligands and studied their physicochemical properties. Several novel series of binuclear cymantrenecarboxylate complexes of lanthanides, [Ln2(μ2-O2CCym)4(η2 -NO3)2(η2 -DME)2], where Ln = Pr (1), Eu (2), Gd (3), Tb (4), Ho (5), Yb (6), Cym = (η5 -C5H4)Mn(CO)3), DME = CH3OCH2CH2OCH3; [Ln2(μ-О,η2 - O2CCym)2(μ2-O2CCym)2(η2 –ООССym)2(py)4]·2py, where Ln = Pr (7), Sm (8), Eu (9), Gd (10); [Ln2(μ-О,η 2 -O2CCym)2(μ2-O2CCym)2(η 2 –О2ССym)2(DMSO)4], where Ln = Tb (11), Dy (12), the trinuclear complex [Yb3(μ-О,η2 -O2CCym)2(μ2-O2CCym)4(η2 -NO3)3(η2 -DME)2] (13) and the polymeric one [Er(η 2 -O2CCym)2(μ-O2CCym)4Er(H2О)4]n·3nTHF·xPhMe (14) were synthesized and characterized by X-ray diffraction. Magnetic, spectral and luminescent properties of selected complexes were studied. In different complexes of Gd weak anti- or ferromagnetic interactions were found; in complexes of Tb ferromagnetic interactions prevail. Cymantrenecarboxylate ligands appreciably suppress Eu3+ luminescence and determine the spectral and the fluorescent properties of the compounds. Thermolysis of complexes in air affords LnMn2O5 (1 - 6) or mixtures of LnMn2O5 and Mn2O3 (7 - 14)