Manufacturing atomically-precise functional nanoarchitectures with tailored physics at well-defined device interfaces is a frontier in bottom-up nanomaterial [1,2] and condensed matter design [3]. A long-standing challenge in the field is the integration of functional elements in proof-of-concept devices. One strategy to alleviate the cumbersome device integration of single-layered molecular systems, is to achieve increasing control over vertical supramolecular heterojunctions and multilayers, so as to transition from ‘on-surface’, to ‘out-of-surface’ surface science protocols. [more]