A series of terminally functionalized polyisobutylene (PIB) derivatives were synthesized and tested as agents for magnetic nanoparticle solubilization. PIB-bound catechol was found to be the best functionalized polyolefin at effecting such solubilization based on UV-vis spectroscopic absorbance measurements and thermogravimetric analysis. The PIB-modified magnetic nanoparticles obtained from grafting reactions contain up to 32 wt % of MNPs. They easily disperse in nonpolar and modestly polar organic solvents. The high loading (>50 wt %) of the PIB-modified magnetic nanoparticles even in alkane solvents makes the resulting solutions magnetically susceptible. This was illustrated by preliminary work where PIB-modified MNPs formed solutions with heptane that could be magnetically separated from water. These PIE-modified magnetic nanoparticles were also shown to be highly soluble in low melting polyethylene waxes and in liquid poly(alpha-olefin)s.