Different protected thiol-functionalized initiators were prepared and used to-polymerize end-functionalized poly(3-hexylthiophene)s in which the spacer between the thiol and the P3HT chain is varied. The protected thiol P3HTs were in situ deprotected and anchored onto Au nanoparticles (NPs) to form P3HT/Au hybrids. The influence of the length of the linker between the P3HT and the Au NP surface on the fluorescence quenching was investigated. The strongest quenching was observed for the shortest linkers. Also, a protected thiol poly(3-octylselenophene) (P3OS) was polymerized and anchored together and separately with P3HT to a Au NP. The effect of the presence of P3OS on the quenching was investigated, and an additional quenching was observed when P3OS is anchored on the same NP as P3HT. For all polymers, H-1 NMR and MALDI-ToF analysis confirmed the successful functionalization and strong control over the polymerization.