A unified view on the dynamics of the intercalation reaction in dichalcogenides and in graphite is presented. The in-situ observed changes in the conductivity, X-ray and electron diffraction, optical absorbance and esr (in graphite) during the reaction indicate that electronic changes produced by the chemisorption of adducts on the basal surface of the crystals are responsible for the subsequent expansion of the lattice and intercalation. In pristine graphite two Dyson shaped esr absorption of the electron and the hole carriers are resolved (in high vacuum). The extreme sensitivity of the surface conductivity is used to verify that adsorbed gases change the electronic properties of the surface states before the intercalation reaction begins. In all cases the critical temperature Tc, for periodic lattice distortion/charge density (PLD/CDW) formation in the host lattice is raised to temperatures above the melting point of the intercalate layer. We compare layer dichalcogenides and graphite intercalated compounds with other low dimensional materials (polyacetylene) in view of the Jahn-Teller Theorem in band materials.