Ionic liquids (ILs) indicate a modern class of ionic solvents of bulky cations and anions, with the feasibility of tuning their thermal and physical properties for various applications. In the current work new choline salicylate derivatives based ILs such as Choline Salicylate, [Ch][SA]; Choline para-Methyl Salicylic Acid, [Ch][p-MSA]; Choline para-Amino Salicylic Acid, [Ch][p-ASA]; Choline para-Nitro Salicylic Acid, [Ch][p-NSA]; Choline para-Chloro Salicylic Acid, [Ch][p-Clsa]; Choline para Hydroxy Salicylic Acid, [Ch][P-HSA]; Di-Choline Salicylic Acid, [Ch]2[SA]; Di Choline p-Methyl Salicylic Acid, [Ch]2[MSA]; Tri-Choline Hydroxy Salicylic Acid, [Ch]3[HSA] and Choline Acetyl Salicylic Acid, [Ch][AcSA] were synthesized and characterized using various techniques like NMR, IR, TGA and HPLC-MS. These ILs are used to study their effect as additives on the properties of aqueous anionic surfactant sodium dodecyl sulfate (SDS) solutions and the ability of the studied ILs to form aqueous biphasic systems (ABS) for application in extraction. Understanding the effect of (ILs) as additives on the properties of aqueous SDS surfactant solutions is intensely important because of the various applications of surfactant-based in the industry. Aggregation behavior of SDS were investigated in the absence and presence of 5 mM ILs in aqueous solutions. The critical micelle concentration (CMC) values have been estimated for different IL+ surfactant systems at three different temperatures 288.15, 298.15 and 308.15 K using different techniques like electrical conductivity and surface tension. The results indicate that the addition of all employed ILs to SDS surfactant leads to a decrease in the CMC in this order: [Ch][p ClSA]> [Ch][p-NSA] > [Ch][p-ASA] > [Ch][p-HSA] > [Ch][SA] > water. The obtained CMC values are employed to determine the thermodynamic parameters of micellization such as standard free energy (∆𝐺𝑚 ° ), standard enthalpy (∆𝐻𝑚 ° ), and standard entropy (∆𝑆𝑚 ° ). The values of these parameters indicate that adding ILs adjust the micellization properties of SDS solution. Parameters such as maximum surface excess concentration (Г𝑚𝑎𝑥), minimum area per molecule (𝐴𝑚𝑖𝑛 ), surface pressure at CMC (𝜋𝐶𝑀𝐶), the efficiency of adsorption (𝑝𝐶20) and packing parameters (𝑃) were calculated and analyzed in this study to predict the interfacial behavior of SDS surfactant for a better understanding of the rule of ILs' anions in upgrading their efficiencies in comparison with the aqueous system. The values of the standard Gibbs free energy of micellization (∆𝐺𝑚 ) are negative for all systems indicating that the micellization is a spontaneous process Recently, choline-based biphasic systems (ABS) have a great interest because of their "green" separation processes for the extraction of value-added compounds. We study the effects of the anion of the IL in forming the ABS with tri-potassium phosphate salt (K3PO4). Seven ILs were able to form ABS. The used ABS system "IL+ salt + water" was determined at 298.15 K & atmospheric pressure and the respective solubility curves, tie-lines, and tie-line lengths are reported. The trend in capability of forming ABS was observed in the following order: [Ch]3[p-HSA] > [Ch]2[p-MSA] > [Ch]2[SA] >[Ch][AcetylSA] > [Ch][p-ASA] > [Ch][p-MSA] > [Ch][SA]. The solubility curve was fitted to the Merchuk equation and tie lines were calculated from mass phase fractions based on the lever arm rule that are described using the Othmer Tobias and Bancroft equations. Also, the ABS is evaluated through its extraction capability for caffeine using partition coefficient which found to be greater than one in all studied systems indicating an efficient extraction.