Tetravalent thorium and uranium complexes with cucurbit[5]uril (Q[5]) were investigated with eight new complexes being synthesized and structurally characterized. [Th(Q[5])(OH)(H2O)(2)](6)center dot 18NO(3)center dot nH(2)O (1) has a hexagonal nanowheel structure with each of the six Th4+ ions being cap coordinated by a Q[5] and monodentate-coordinated to the nearby Q[5]. [Th(Q[5])(HCOO)(H2O)(4)][Th(NO3)(5)(H2O)(2)](2)[Th(NO3)(3)(HCOO)(H2O)(2)](0.5)center dot NO3 center dot nH(2)O (2) has a heteroleptic mononuclear structure with a Th4+ ion cap-coordinated on one side of the Q[5] portal and monodentate-coordinated to a formate anion inside the Q[5] cavity. [KTh1.5(Q[5])Cl(NO3)(3)][Th(NO3)(5)(H2O)(2)]center dot 2NO(3)center dot 2.5H(2)O (3) has a heterometallic structure with both Th4+ and K+ ions each occupying one side of the two Q[5] portals forming a capsule. [CsTh(Q[5])Cl(NO3)(2)(H2O)(3)]center dot 2NO(3)center dot nH(2)O (4) has a heterometallic 1D polymeric structure with both Th4+ and Cs+ ions each occupying one side of the two Q[5] portals, forming monomers which are linked together by sharing two water molecules and one carbonyl oxygen atom between Th4+ and Cs+ ions. [Th(Q[5])Cl(H2O)][CdCl3][CdCl4]center dot 0.5HCl center dot 4H(2)O (5), [Th(Q[5])Cl(H2O)][Ru2OCl9(H2O)]center dot 0.5HCl center dot 9.5H(2)O (6), [Th(Q[5])Cl(H2O)][IrCl6](1.5)center dot 3H(2)O (7), and [U(Q[5])Cl(H2O)][ZnCl3(H2O)][(ZnCl4)]center dot 8H(2)O (8) have similar 1D polymeric structures with Th4+/U4+ ions cap-coordinated on one side of a Q[5] and bidentate coordinated to the nearby Q[5]. The transition metal chlorides act as anions for charge compensation as well as structure inducers via cation anion interactions forming various anion patterns around the 1D polymers. Actinide contraction has been observed in the early actinide series.