The remarkable structure-dependent electronic, mechanical, optical, and magnetic properties [1][2][3][4] of carbon nanotubes (CNTs) have triggered intensive study directed towards numerous applications in many different fields. [5] To this end,CNTs are expected to be controllably assembled into designed architectures as integral components of composites and/or supramolecular structures. Many of the future applications of single-walled carbon nanotubes (SWNTs) [6] and multiwalled carbon nanotubes (MWNTs) [7] are highly dependent on their electronic properties and, in this context, their ballistic transport behavior and long electron-mean-free-path have shown their potential as molecular wires. [6] In the case of SWNTs, depending on their chirality [1] and diameter, [8,9] either metallic or semiconductor behavior can be obtained. The electronic properties of MWNTs, although less well known, have been shown to exhibit either metallic [10] or semiconducting [11] characteristics depending on their outermost shell. Intershell interactions in these MWNTs are weak, confining electrical transport to the outermost shell.[9] The electrical properties of MWNTs can be manipulated by using current-induced oxidation to break down systematically the outermost shells in a layer-by-layer (LbL) fashion, opening the possibility of selecting tubes with desired electrical properties. [12] Recently, novel strategies have been devoted to alter the physical properties of CNTs by surface modification with organic, inorganic, and biological species, [13] rendering functional CNT composites for novel applications.[14] Among these surface modifications, the linkage of semiconductor nanocrystals to CNTs has emerged as a novel strategy to change the optical and electronic properties of the nanotubes. Nanoparticles of II-VI semiconductors are highly luminescent, inorganic crystals which possess size-tunable electronic and optical properties resulting from quantum confinement of the photoexcited exciton.[15] Solar cells, biological sensors, and light-emitting devices are some envisioned applications of these quantum dots (QDs), since their response wavelength can be tuned depending on their size, [16] and once assembled they reveal interesting collective physical properties. [15,17] Additionally, CNTs can be used as templates for the formation of linear assemblies which present promising applications as integral components in optical and electronic devices. All these applications require a better understanding of the influence of separation between CNTs and QDs on the electronic and optical properties. Several examples of QD-CNT composites have been reported, [18] including CNT-QD junctions using CdTe in ozonized CNTs, [18c] CNT/CdS core-shell nanowires produced by chemical reduction, [18j] and heterojunctions of amine-terminated ZnS-coated CdSe@ZnS on acid-oxidized CNTs.[18e] The formation of these heterostructures was successfully performed despite there being poor control over the surface coverage and the degree of QD clustering onto th...