This investigation aimed to assess the host behaviour of (4R,5R)-bis(diphenylhydroxymethyl)-2-spiro-1’-cyclohexane-1,3-dioxolane (T6) in mixtures of potential guest compounds pyridine and the methylpyridines as well as in these mixtures when dissolved in aqueous solutions.  At the outset, T6 was revealed to possess the ability to form 1:1 host:guest (H:G) inclusion compounds with each of pyridine (PYR) and 2-, 3- and 4-methylpyridine (2MP, 3MP and 4MP) in single solvent crystallization experiments.  When the host was exposed to the guest compounds in the presence of water, different H:G ratios were observed.  In the presence of water, T6 formed a 2:1 H:G inclusion complex with PYR and 4MP, and a 1:1 H:G complex with 3MP.  2MP did not form an inclusion complex with T6 when in the presence of water.  Furthermore, the host compound demonstrated enhanced selectivities in PYR/MP mixtures: preferred guests were PYR and 3MP (in the absence of PYR), followed by 4MP and then 2MP. Subsequent binary guest competition experiments showed that T6 may be employed in order to effectively separate very many of these mixtures in this way, and significant selectivity coefficients (K) were calculated in numerous instances. Thermal analyses demonstrated that the thermal stabilities of these complexes decreased in the guest order PYR > 3MP > 4MP > 2MP, thus agreeing with the host selectivity in guest mixtures. The aqueous studies revealed that T6 is able to extract these potential water foulants from wastewater.