A class of compounds sharing the properties of 2D materials and electrolytes, namely 2D electrolytes is described theoretically and demonstrated experimentally. 2D electrolytes dissociate in different solvents, such as water, and become electrically charged. The chemical and physical properties of these compounds can be controlled by external factors, such as pH, temperature, electric permittivity of the medium, and ionic concentration. 2D electrolytes, in analogy with polyelectrolytes, present reversible morphological transitions from 2D to 1D, as a function of pH, due to the interplay of the elastic and Coulomb energies. Since these materials show stimuli-responsive behavior to the environmental conditions, 2D electrolytes can be considered as a novel class of smart materials that expand the functionalities of 2D materials and are promising for applications that require stimuli-responsive demeanor, such as drug delivery, artificial muscles, and energy storage.