A new series of 12 cyclic ammonium-based room temperature ionic liquids (RTILs) containing an alkylphosphite anion have been synthesized by an alkylation reaction between cyclic tertiary amines and dialkylphosphite. This method constitutes an eco-friendly pathway to RTILs that does not generate any secondary byproducts and avoiding the metathesis reaction involving uses of nonfriendly or expensive salts. Their physicochemical and electrochemical properties have been investigated. The temperature dependency of density, dynamic viscosity, and ionic conductivity were determined at temperatures varying from 293.15 to 323.15 K and were discussed on a structural basis. For the prepared RTILs, the viscosity values are fairly high and low ionic conductivity as compared to usual ILs. The transport properties were found to be temperature-dependent and followed the Arrhenius law. The RTILs potential windows (Delta E) are comprised between 3.00 and 4.77 V. The electrochemical stability seems to be influenced by the alkyl side chain. An increasing in the carbon number of the cation and anion side chain decreases the electrochemical window of RTILs. The correlation between ionic conductivity and viscosity was studied on the basis of the Walden rule, and the new RTILs can be classified as associated ionic liquids (AILs), an intermediate between a true, ionic liquid and a molecular species.