The capability to adjust the properties of ILs by combining different cations and anions leads to the name of “designer solvents” for ILs. There is a steadily growing interest for the use of ILs in electrochemical applications such as supercapacitors and rechargeable batteries. In this work, the highly parameterized, empirical exchange–correlation functional at M06–2X/6-311++G(d,p) level of theory were employed to investigate the influence of various cations and anions on electrochemical and physicochemical properties of the thirty-six ILs formed from a combination of para−X−phenyl methylimidazolium ([X−PhMIM]+: X=NH2, OH, OCH3, CH3, H, F, CHO, CN and NO2) cations and the four different conventional anions (Y1–4 =CH3COO−, NO3 −, BF4 − and PF6 −). The potentials of the cathodic (VCL) and anodic (VAL) limits, electrochemical windows (ECW), CT values, volumetric and thermodynamic properties, interaction energy, enthalpy of formation of cations, Gibbs free solvation energy, topological properties and NMR one- and two bonds spin–spin coupling constants (SSCCs) were predicted.