Poly(3-hexylthiophene)s were synthesized with phosphonic ester, pyridine, thiol, and phenol end-groups using functionalized air-stable Ni initiators. The protected thiol- and phenol-functionalized P3HTs were converted into thiol and phenol P3HTs by quantitative postpolymerization reactions. H-1 NMR and MALDI-ToF analysis showed very high degrees of functionalization and strong control over the polymerization except for the pyridine functionalized P3HT. These functional end-groups were used to prepare hybrid materials from a broad variety of nanoparticles, including metal oxides, quantum dots, and noble metals.