Those residues do however not result in similar effect, as observed for the defined heterostructures. The free-oriented phenyl radicals restore the interlayer distances of de-F-G/MoS2, similar to pristine G/ MoS2 thus, recovering the PL intensity of MoS2. Our results prove that chemical functionalization and accompanied tailoring of the distance of 2D layers in heterostructures provide major effects on the PL readout. We demonstrate that annealing reverts the readout to another state. Finally, the results indicate that phenyl-groups covalently attached to graphene act at least partially as separate component, thus, the F-G/MoS2 heterostructure can be better described as G/-phenyl/MoS2. With that knowledge in mind, we change our way of thinking about functionalized 2D materials.