InGaAs quantum wires (QWRs) and InGaAs quantum wire-dot coupled structures were formed by selective MBE growth on patterned InP substrates, and attempts were made to realize single-electron transistors (SETs) on them. Investigation of basic optical and transport characteristics of both nanostructures by PL, CL and magnetotransport measurements revealed realization of high quality quantum nanostructures. In the coupled structure, double barrier potential profile essential for SET was realized in a self-organizing fashion without any additional processing. The SETs made on wires showed clear Coulomb oscillations up to 30 K, indicating realization of small quantum dots (QDs) and high potential barriers by this approach.