Halogen bonding (XB) between (iodoethynyl)benzene donors and quinuclidine in benzene affords binding free enthalpies (ΔG, 298 K) between -1.1 and -2.4 kcal mol(-1), with a strong LFER with the Hammett parameter σpara. The enthalpic driving force is compensated by an unfavorable entropic term. The binding affinity of XB acceptors increases in the order pyridine < C═O < S═O < P═O < quinuclidine. Diverse XB packing motifs are observed in the solid state.