The concentration dependence of the 19F spin-lattice relaxation times and the proton chemical shifts has been studied for four hexafluorobenzene-hydrocarbon mixtures. These physical measurements provide no indication of the existence of specific fluorocarbon-hydrocarbon interactions in the hexafluorobenzene-cyclohexane and hexafluorobenzene-benzene systems. The results confirm the existence of a weak interaction in the hexafluorobenzene-mesitylene system. Complex formation is detected in the hexafluorobenzene-dimethylformamide system. The experimental results do not offer any evidence for charge-transfer interactions. A discontinuity is observed in the viscosity-corrected T1 plot as a function of fluorocarbon concentration in the 2,2,2-trifluoroethanol-ethanol system indicating strong mixed hydrogen bonding involving the hydroxyl groups.