<p>Electron transfer and transport constitute the fundamental mechanisms governing the performance of polymeric dielectrics, yet their microscopic nature remains elusive due to the intrinsic complexity of aperiodic condensed states. This investigation presents, for the first time, a computational-experimental exploration on quantitative, real-space orbital electron transfer and quantum electron transport, which have been largely overlooked in aperiodic systems. The energy barrier and spatial confinement of unoccupied frontier orbitals play a pivotal role in regulating electron transfer, which is predictable and experimentally characterizable, and dictates dielectric performance. Additionally, the structure-dependent quantum current strongly influences the macroscopic conduction characteristics. These insights enable precise regulation of dielectric performance via chemically superseding frontier orbitals. We hence apply this approach to a typical polymeric system and propose a design principle comprising three ab-initio descriptors. Our results substantiate the validity of this rationale, offering renewed insights into electron dynamics in aperiodic systems and guiding future dielectric design.</p>