We have carried out a comparative study on three sets of eutectic mixtures based on choline chloride (ChCl) and hydroxyphenol isomers having two hydroxyl groups in ortho-, meta-, and para-position of the aromatic ring, namely catechol (Cate), resorcinol (Reso), and hydroquinone (Hydro), respectively. Differential scanning calorimetry highlighted a different thermal behavior of the mixtures depending on the composition and precursor isomerism. These systems behave as deep eutectic solvents (DESs) with the exception of the ChCl/Cate mixtures at 1:0.75 molar ratio, ChCl/Reso 1:2 and 1:3, and ChCl/Hydro 1:3. Infrared spectroscopy measurements and molecular dynamics simulations show that the stronger hydrogen-bonding (H-bonding) in the mixed states as compared to the pure precursors is key for the formation of a DES. This interaction is mostly reliant on interconnected chloride anion coordination shells thanks to the two hydroxyl groups of the hydroxyphenol molecules, which can bridge between different anions to form an extended H-bond network. This structural arrangement maximizes the interactions and is enhanced by the 1:0.75 and 1:1 molar ratios while increasing the hydroxyphenol concentration is translated into a lowering of the total number of H-bonds formed in the mixture. This is at the base of the different thermal behavior and points at nearly equimolar compositions between the components as ideally suited to achieve a DES from these precursors. The obtained insights are able to explain the structure-property relationship for the studied systems and are deemed useful for more conscious development of these inherently tuneable solvents.