The conductance of a single molecule junction depends on both the chemical nature and conformation of the molecule. In the case of biphenyl molecules, conductance is expected to change with the twist angle between the two phenyl rings, with the planar conformation showing the highest conductance. Using amine link groups, the authors show a clear correlation between molecular conformation and junction conductance in a series of seven biphenyl molecules with different ring substitutions. They find that conductance decreases with increasing twist angle, consistent with a theoretical cosine squared relation for transport through π-conjugated systems. The authors demonstrate that using amine groups instead of thiols or isonitriles results in more reliable and reproducible conductance values. This allows for statistically meaningful average conductance values and the study of molecular properties' impact on junction conductance. Conductance histograms are used to show the most prevalent conductances and the width of distributions reflects microscopic variations. The histograms for 1,4-diaminobenzene and 2,7-diaminofluorene show distinct peaks below the quantum of conductance, with steps indicating conduction through a single molecule. When using a solution containing an equimolar mixture of 1 and 2, the histogram shows two distinct peaks below G₀, corresponding to the conductances of the individual molecules. The results indicate that the molecules do not exchange positions rapidly, supporting that conduction is through a single molecule. The conductance of biphenyl molecules decreases as the twist angle increases and π-conjugation decreases, with the conductance following a cosine squared relation. The authors also show that the conductance of oligophenyl molecules decreases exponentially with the number of phenyl rings, consistent with non-resonant tunneling transport. The data indicate that the electronic effects of substituents do not significantly alter the simple picture of junction conductance being adjusted by decreasing π-overlap. The results agree with predictions of non-resonant tunneling transport through static molecules, and the data reveal that as molecules have more rotational degrees of freedom, the conductance peak broadens. This is due to the molecule being in different average conformations enabled by its rotational degrees of freedom.The conductance of a single molecule junction depends on both the chemical nature and conformation of the molecule. In the case of biphenyl molecules, conductance is expected to change with the twist angle between the two phenyl rings, with the planar conformation showing the highest conductance. Using amine link groups, the authors show a clear correlation between molecular conformation and junction conductance in a series of seven biphenyl molecules with different ring substitutions. They find that conductance decreases with increasing twist angle, consistent with a theoretical cosine squared relation for transport through π-conjugated systems. The authors demonstrate that using amine groups instead of thiols or isonitriles results in more reliable and reproducible conductance values. This allows for statistically meaningful average conductance values and the study of molecular properties' impact on junction conductance. Conductance histograms are used to show the most prevalent conductances and the width of distributions reflects microscopic variations. The histograms for 1,4-diaminobenzene and 2,7-diaminofluorene show distinct peaks below the quantum of conductance, with steps indicating conduction through a single molecule. When using a solution containing an equimolar mixture of 1 and 2, the histogram shows two distinct peaks below G₀, corresponding to the conductances of the individual molecules. The results indicate that the molecules do not exchange positions rapidly, supporting that conduction is through a single molecule. The conductance of biphenyl molecules decreases as the twist angle increases and π-conjugation decreases, with the conductance following a cosine squared relation. The authors also show that the conductance of oligophenyl molecules decreases exponentially with the number of phenyl rings, consistent with non-resonant tunneling transport. The data indicate that the electronic effects of substituents do not significantly alter the simple picture of junction conductance being adjusted by decreasing π-overlap. The results agree with predictions of non-resonant tunneling transport through static molecules, and the data reveal that as molecules have more rotational degrees of freedom, the conductance peak broadens. This is due to the molecule being in different average conformations enabled by its rotational degrees of freedom.