Understanding the properties and behaviors of diluted bitumen/water interfaces under stresses is important for remediating emulsion problems in bitumen production. We studied the dilational interfacial rheology of toluene-diluted mineral-free Athabasca bitumen, its n-pentane (n-C5) asphaltenes, and partially deasphalted Athabasca bitumens in a NaHCO3 solution. n-Heptane (n-C7) added in increasing mass ratios to diluted bitumen produced the partially deasphalted bitumens. The solvent-free deasphalted bitumens and the precipitated n-C7 asphaltenes were recovered for study. The number averaged molecular weight (M-n) of the samples was first measured as a function of the mass concentration in toluene. The slopes of these curves indicated that asphaltenes showed higher aggregation tendencies than the bitumens. This tendency was reduced significantly for the deasphalted bitumens. For all oscillation frequencies studied, the interfacial viscoelastic modulus of Athabasca bitumen-in-toluene reached a maximum at 0.865 g.L-1 (0.1 wt%) bitumen, then declined as the bitumen concentration increased. The n-C5 asphaltenes-in-toluene made up at the same concentration at which they occur in the diluted bitumen showed higher elastic and viscous moduli than those for the diluted source bitumen, at all frequencies tested. Both systems showed direct dependence of viscoelasticity on the logarithm of frequency; the n-C5 asphaltenes showed a higher viscoelasticity gradient than that for the bitumen. Distinct differences between the interfacial properties for asphaltenes-in-toluene/water vs source bitumens-in-toluene/water were observed. The interfacial viscoelasticity values for the partially deasphalted bitumens also show apparent dependence on the mass ratio of resins to residual asphaltenes (R/A). Different asphaltene aggregates present in the bitumens may also influence the R/As correlated with reduced elasticity. The interfacial behaviors of asphaltenes only in toluene are thus not indicative of those of bitumens.