The ability of the propargylated calix[4]arene ligand H3L (= 25-(2-propynyloxy)-26,27,28-trihydroxy-calix[4]arene) to bind lanthanide ions has been studied. The triply deprotonated ligand was found to support dinuclear neutral complexes of composition [Ln2L2(MeOH)4] (Ln= La (1), Gd (2), Tb (3), Tm (4)). Spectroscopic data for 1–4 as well as X-ray crystallographic analysis of single crystals of 1∙(MeOH)2 and 2∙(MeOH)2 reveal that two [LnL] entities dimerize via two phenolato groups to generate a centrosymmetric (MeOH)2O3Ln(μ-O)2LnO3(OHMe)2 core structure. The Ln3+ ions reside in a distorted mono-capped octahedral coordination environment. Squid magnetic measurements for the Gd3+ and Tb3+ complexes agree with the formulation as dinuclear compounds, and reveal the presence of very weak antiferromagnetic exchange interactions (J < 0.1 cm−1). The ability of the La3+ complex to react with azides in a click reaction is also demonstrated.