General variations of electronic states are discussed, and the state "vertical" and "horizontal" displacements are explored. Quantum dynamics of the wave function modulus and phase components is examined, and the associated continuity relations are summarized. The probability and current contributions to overall information-theoretic (IT) descriptors of the state global and gradient entropy/information content are identified. These resultant measures are used to determine the phase equilibria in molecular systems. The currents corresponding to the entropy- and information-optimum phases are explored, the classical (probability) and nonclassical (current) flows in molecular information systems are identified, and probability interpretation of equidensity orbitals yielding the prescribed electron density is given. The physical equivalence of variational principles for the electronic energy and resultant gradient-information in open systems is stressed. It implies that their populational derivatives have the same capacity in describing charge transfer phenomena in molecules and their fragments. Illustrative application in determining thermodynamic equilibria and optimum charge transfer in molecular systems is discussed, and implications of the molecular virial theorem for bond-formation process and chemical reactions are investigated. The crucial role of the resultant gradient-information in chemical bonding is emphasized, and the Hammond postulate of reactivity theory is shown to be indexed by the reaction-coordinate derivative of electronic kinetic energy at the transition-state complex.