The electronic transmission of fifteen potential configurations of single-phenanthrene junction has been theoretically investigated. The structures include para-para, para-meta, and meta-meta combined with phenyl pendant group and substituted nitrogen atom. The results show that the para-meta, which offers a tunable antiresonance in the HOMO-LUMO gap, is the most suitable for synthesizing nano-device. The antiresonance is susceptible (unsusceptible) to the heteromotif location at site four (five). Hence, our paper presents the appropriate hetero-motif conditions—type and location— to synthesize molecular devices with the desired electronic conductance. The study also deepen the understanding of the molecular conductance by demonstrating the active and inactive sites to create and tune antiresonances. It finally introduces the essential impact of connectivity, quantum interference, and aromaticity in controlling the conductance of single-phenanthrene junction.