An adsorption study of Athabasca vacuum residue (VR) and its visbroken (VB) products over in-house made macroporous Ca-kaolin and Ca-Ba-kaolin adsorbents was carried out at ambient temperatures. Adsorption experiments were performed for 120 min in toluene solution of the adsorbates, monitored via ultraviolet-visible (UV-vis) spectrophotometry to determine the corresponding uptake. The extent of the uptake was correlated with molecular parameters obtained from H-1 and C-13 nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, and solubility profiles to determine which properties may enhance the adsorption. It was found that the severity of thermal cracking induced noticeable changes in solubility profiles, aromaticity (f(a)), total naphthenic carbon (TNC), and secondary methylene groups on the corresponding products. Furthermore, heteroatom content also changed with 545 degrees C+ conversions, leading to products with decreased sulfur contents and enhanced in nitrogen and oxygen as the severity increases. Higher uptakes were observed in adsorbates with more aromaticity, higher solubility profile, and higher nitrogen and oxygen contents. Trends between these molecular properties with uptakes allowed for the prediction of the potential adsorption capacity of the thermal-cracked products over this type of adsorbent.