More than 50 ionic liquids were prepared by using imidazolium, quaternary ammonium, and guanidinium cations and various anions. In these series, different cationic structures such as 1-benzyl-3-methylimidazolium [Bzmim](+), 1,3-dibenzylimidazolium [BzmiBz](+), 1-octyl-3-methylimidazolium [C(8)mim](+), 1-decyl-3-methylimidazolium [C(10)mim](+), tricapryl-methyl-ammonium [Aliquat](+), benzyltriethyl-ammonium [BzTEA](+), phenyltrimethyl-ammonium [PhTMA](+), and dimethyldihexylguanidinium [DMG](+) were combined with anions, p-toluenesulfonate [TSA](-), dicyanoamide [DCA](-), saccharine (2-sulfobenzoic acid imide sodium salt) [SAC]-, trifluoroacetate [TFA](-), bis(trifluoromethanesulfonyl)-imide [TfO](-), trifluoromethanesulfonate [TfO](-), and thiocyanate [SCN](-). Important physical data for these ionic liquids are collated, namely solubility in common solvents, viscosity, density, melting point and water content. Apart from the viscosity, the Newtonian and non-Newtonian behavior of these ionic liquids is also disclosed. Stability of these ionic liquids under thermal, basic, acidic, nucleophilic, and oxidative conditions was also studied. The features of the solid-liquid phase transition were analyzed, namely the glass transition temperature and the heat capacity jump associated with the transition from the non-equilibrium glass to the metastable supercooled liquid. A degradation temperature of each ionic liquid was also determined. Comparisons of the properties of various ionic liquids were made.