The recent synthesis of interfaces and heterostructures with atomic precision has revealed numerous new and unexpected phenomena. The order of magnitude enhancement of the superconducting properties of FeSe in the ultrathin 2D limit is an example of such a surprise. In this talk I will discuss recent efforts to combine molecular beam epitaxy (MBE) with various in situ and ex situ techniques to determine the origins of the Tc enhancement. Angle resolved photoemission spectroscopy (ARPES), reveals how the electrons in the FeSe monolayer couple with the phonons in the underlying substrate to boost the superconducting properties to record breaking Tc’s for this class of materials. Time resolved ARPES (tr-ARPES) and time resolved x-ray diffraction (tr-XRD) are combined in a lock-in experiment to quantify the electron-phonon coupling in these materials with femtosecond precision.