Abstract
Mono and (bis)benzimidazoliums were evaluated both experimentally and computationally for their potential as building blocks of pseudopolyrotaxane axles. Their aggregation and optical behavior, along with their potential to form a [2]pseudorotaxane with dibenzyl-24-crown-8, was studied through the synergistic application of 1D/2D and diffusion ordered NMR spectroscopy, ultraviolet-visible & fluorescence spectroscopy, and time-dependent density functional theory. Their unique optical behaviour was measured and modeled as a function of protonation state, solvent, and concentration. The axles show strong solvochromaticism and a very pronounced concentration-dependent optical profile. This axle with multiple recognition sites, has the potential to form pseudorotaxanes with tunable optical behavior.