The synthesis of digalactoside 1Gal was previously described in a study of luminescent lectin-sensing by Tb(III)-glycoconjugate complexes. The complex of 1Gal was not an effective sensor for LecA, but analogues with flexible spacers between the carbohydrate motif and the triazole function as 'switch-on' sensors for unlabelled bacterial lectin LecA. We have since further investigated affinity of 1Gal by isothermal calorimetry (ITC) and surface plasmon resonance (SPR) to establish that this compound has surprisingly high affinity for PA's galactophilic lectin, considering the short spacing between galactose epitopes, precluding chelate binding. In ITC experiments (Figure ), binding data for 1Gal indicated this digalactoside binds to LecA in a 1:1 stoichiometry, only availing of one galactose epitope at a time, which is unsurprising, due to the relatively wide spacing of neighbouring receptor sites in the LecA tetramer (ca. 29 Å). An average Kd of 9.6±0.7 μM for LecA was determined. The interaction had a typical enthalpy for a single carbohydrate recognition event with LecA of about -30 kJ/mol. Moreover, SPR data, determined by immobilising LecA on a chip to investigate kinetic interactions also gave a low micromolar affinity of 6.6±0.5 μM, using a steady-state fitting model and 5.9±0.1 μM by kinetics fitting model. A more flexible related ligand 5 (Figure S-21, ESI †), with a triethyleneglycol linker had marginally better affinity by ITC (6.5 ± 0.1 μM) and comparable Kd by SPR (6.0 ± 1 μM) indicating that for this motif, the added length and flexibility conferred by the linker does not affect affinity to the lectin to a major extent. These strong interactions were noteworthy, as the structure of 1Gal is synthetically simpler than many chelating glycoconjugates, leading to higher yields, without sacrificing much affinity; thus opening many possibilities to test 1Gal as part of inorganic complexes for bacteriostatic or antimicrobial effects. These results encouraged us to develop this ligand further and make derivatives with other carbohydrate moieties by leveraging the efficiency of Cu-catalysed click cycloadditions, and complexed these to a variety of metals as potential antibiofilm agents targeting PA's lectins.