A series of calixarene bismuth and antimony complexes have been fully characterized by NMR, X-ray, IR, UV/vis, and elemental analysis. The reactions of SbCl3 with the monosodium salt of p-tert-butylcalix[4]arene (Bu(t)C4), Bu(t)C4 center dot Na, and the tetralithium salt of para-tert-butylcalix[4]arene, Bu(t)C4 center dot Li-4, afforded two diantimony calix[4]arene complexes Bu(t)C4(SbCl)(2), with different H-1 NMR spectra and different THF coordination, but the same core structures. Other calix[4]arene antimony complexes (HC4(SbCl)(2) 2 and AC4(SbCl)(2) 3, diantimony chloride complexes of calix[4]arene and p-allylcalix[4]arene) and calix[4]arene bismuth complexes (Bu(t)C4(BiCl2)(2)Li-2 4, HC4(BiCl2)(2)Li-2 center dot 6DMSO 5, and AC4(BiCl2)(2)Li-2 center dot 4THF 6) were prepared by the reactions of MCl3 (M = Sb or Bi) with RC4 center dot Li-4 (13 = Bu-t, H, or allyl) in a 2:1 molar ratio in THF. The same strategy was applied for Bu(t)C8 (p-tert-butylcalix[8]arene), and the desired bismuth complex [Bu(t)C8(BiCl2)(4)(mu-Cl)(2)Li-6][4THF center dot 7DME] 12 was successfully synthesized. Complex 12 contains a planar Bi-4 core with four terminal chlorine atoms, which adopt a syn arrangement with respect to the plane defined by four bismuth atoms, and orient away from each other. A calix[4]arene monobismuth complex 11 was prepared by the reaction of Bi(OBut)(3) with the 1,2-disubstituted benzyl ether of calix[4]arene, Complexes 1-6 contain central planar M-2(mu-O)(2) (M = Sb or Bi) four-membered rings, similar to four-membered rings observed in other calix[4]arene main group metal complexes. Intramolecular bismuth-arene 7 interactions are observed in complexes 4-6 and 11 but not 12.