Reaction of [UO2Cl2(THF)3] with 3 equiv of LiC6Cl5 in Et2O resulted in the formation of the first uranyl aryl complex, [Li(Et2O)2(THF)][UO2(C6Cl5)3] ([Li][2.1]) in good yields. Subsequent dissolution of [Li][2.1] in THF resulted in conversion to [Li(THF)4][UO2(C6Cl5)3(THF)] ([Li][2.2]), also in good yields. DFT calculations reveal that the U-C bonds in [Li][2.1] and [Li][2.2] exhibit appreciable covalency. Additionally, the 13C chemical shifts for their Cipso environments are strongly affected by spin-orbit coupling  a consequence of 5f orbital participation in the U-C bonds.Reaction of AnCl4(DME)n (An = Th, n = 2; U, n = 0) with 5 equiv of LiC6Cl5 in Et2O resulted in the formation of homoleptic actinide-aryl “ate” complexes [Li(DME)2(Et2O)]2[Li(DME)2][Th(C6Cl5)5]3 ([Li][3.1]) and [Li(Et2O)4][U(C6Cl5)5] ([Li][3.2]). Similarly, reaction of AnCl4(DME)n (An = Th, n = 2; U, n = 0) with 3 equiv of LiC6Cl5 in Et2O resulted in formation of heteroleptic actinide-aryl “ate” complexes [Li(DME)2(Et2O)][Li(Et2O)2][ThCl3(C6Cl5)3] ([Li][3.3]) and [Li(Et2O)3][UCl2(C6Cl5)3] ([Li][3.4]). Density functional calculations show that the An-Cipso -bonds are considerably more covalent for the uranium complexes vs. the thorium analogues, in line with past results. Additionally, good agreement between experiment and calculations is obtained for the 13Cipso NMR chemical shifts in [Li][3.1] and [Li][3.3]. The calculations demonstrate a deshielding by ca. 29 ppm from spin-orbit coupling effects originating at Th, which is a direct consequence of 5f orbital participation in the Th-C bonds. Reaction of [Ln(NO3)3(THF)4] (Ln = La; Ce) with 4 equiv of LiC6Cl5 in Et2O resulted in the formation of the homoleptic lanthanide-aryl “ate” complexes [Li(THF)4][La(C6Cl5)4] ([Li][4.1]) and [Li(THF)4][Ce(C6Cl5)4] ([Li][4.2]). These complexes represent the first isolated homoleptic perchlorophenyl complexes for the lanthanides. In the solid state, both [Li][4.1] and [Li][4.2] exhibit octa-coordinate lanthanide centers, with four Ln-C σ-bonds and four ClLn dative interactions involving the ortho-Cl atoms of the C6Cl5 ligands. Despite this apparent steric saturation, both [Li][4.1] and [Li][4.2] are highly temperature sensitive and quickly decompose in solution at room temperature. Density functional calculations show that the Ln-Cipso donation bonds feature only weak 4f participation (e.g., ~1% 4f weight for [4.1]−). Nonetheless, the 13C chemical shift for the Cipso nuclei of [4.1]− includes ca. 8 ppm of deshielding from spin-orbit coupling effects from the 4f (and 5d) participation in its La-C bonds. Reaction of [UO2Cl2(THF)2]2 with in situ generated LiFmes (FmesH = 1,3,5-(CF3)3C6H3) in Et2O resulted in the formation of the uranyl aryl complexes, [Li(THF)3][UO2(Fmes)3] ([Li(THF)3][5.1]) and [Li(Et2O)3(THF)][UO2(Fmes)3] ([Li(Et2O)3(THF)][5.1]), in good to moderate yields after crystallization from hexanes or Et2O, respectively. Both complexes were characterized by X-ray crystallography and NMR spectroscopy. DFT calculations reveal that the Cispo resonance in [5.1]− exhibits a deshielding of 51 ppm from spin-orbit coupling effects originating at uranium, which indicates an appreciable covalency in the U-C bonding interaction. The reaction of [Cp3AnCl] (An = Th, U) with in situ generated 1-lithium-2,2-dipenylcyclopropane results in the formation of [Cp3An(2,2-diphenylcyclopropyl)] (U = 6.1, Th = 6.2), in good yield. Reduction of 6.1 with KC8, in the presence of 2.2.2-cryptand, results in formation of a rare U(III) alkyl complex, [K(2.2.2-cryptand)][Cp3U(2,2-diphenylcyclopropyl)] (6.3). Thermolysis or photolysis of 6.1 for 10 d in toluene results in isomerization to the U(IV) 1-allyl complex, [Cp3U(1-3,3-diphenylallyl)] (6.4). Moreover, photolysis of 2 in THF for 9 h at room temperature results in isomerization to the U(III) 1-allyl complex, [K(2,2,2-cryptand)][Cp3U(1-3,3-diphenylallyl)] (6.5). Both 6.4 and 6.5 were fully characterized. In addition, selective labelling of the Cα positions of 6.1 and 6.3 with deuterium revealed that cyclopropyl ring-opening occurs via distal C-C bond cleavage via a hypothesized η3-allyl intermediate. The reaction of [Cp3Th(3,3-diphenylcyclopropenyl)] with 1 equiv of LDA results in the formation of a thorium allenylidene complex, [Li(Et2O)2][Cp3Th(CCCPh2)] ([Li(Et2O)2][7.1]) in good yield. Additionally, deprotonation of [Cp3Th(3,3-diphenylcyclopropenyl)] with 1 equiv of LDA, in presence of 12-crown-4 or 2.2.2-cryptand, result in the formation of discrete cation/anion pair of thorium allenylidene complexes, [Li(12-crown-4)(THF)][Cp3Th(CCCPh2)] ([Li(12-crown-4)(THF)][7.1]) and [Li(2.2.2-cryptand)][Cp3Th(CCCPh2)] ([Li(2.2.2-cryptand)][7.1]), respectively. Interestingly, complex [Li(Et2O)2][7.1] undergoes dimerization upon standing at room temperature resulting in the formation of [Cp2Th(CCCPh2)]2 (7.2), via loss of LiCp. In addition, the reaction of [Li(Et2O)2][7.1] with MeI results in electrophilic attack at the Cγ carbon atom leading to the formation of a thorium acetylide complex, [Cp3Th(CCC(Me)Ph2)] (7.3), which can be isolated in 83% yield upon work-up. Reaction of [Li(Et2O)2][7.1] with benzophenone results the formation of 1,1,4,4-tetraphenylbutatriene (7.4) in 99% yield, according to integration against an internal standard. Furthermore, density functional theory (DFT) calculations were performed to analyze the bonding in [7.1] and 7.2 revealing significant electron delocalization across the allenylidene ligand. Additionally, calculations of the 13C NMR chemical shifts for the Cα, Cβ, and Cγ environments of the allenylidene ligand were in good agreement with experimental. The calculations reveal modest deshielding induced by spin-orbital effects originating at Th due to the involvement of the 5f orbitals in the Th-C bonds. The reaction of AnCl4(DME)n (An = Th, n = 2; U, n = 0) with 4 equiv of [Li(TMEDA)2][1,2-S2C6H4] in THF resulted in the formation of homoleptic actinide thiolate complexes, [Li(THF)2]4[Th(1,2-(S2)C6H4)4] (8.1) and [Li(TMEDA)]4[U(1,2-(S2)C6H4)4] (8.2), which can be isolated in moderate yields. Additionally, reaction of [UO2Cl2(OPPh3)2] with 2 equiv of KMMP (MMP = methyl-3-mercaptopropionate) in THF results in immediate formation of dark red solution to afford the isolation of [UO2(MMP)2(OPPh3)2] (8.3). Furthermore, reaction of [UO2Cl2(OPCy3)2] with 2 equiv of NaMMP in THF result in the formation of [UO2(MMP)2(OPCy3)2] (8.5).