We report on the fabrication and characterization of unprecedented anodized aluminum oxide (AAO) templates and their replication to yield dye-functionalized polymeric nanotubes with modulated outer diameters between 83 ± 3 nm and 167 ± 8 nm by wetting the templates with a polymer solution. In particular, modulated diameter AAO nanopores with interpore distances of 234 ± 9 nm, 273 ± 6 nm, and 332 ± 11 nm and diameters ranging between 40 nm and 120 nm were fabricated with segment lengths of the thinner and the thicker pore portion of 250 nm to ≥100 μm and 300 nm to 18 μm, respectively, in a highly controlled continuous anodization process. In this process the temperature at the Al/Al₂O₃ interface was altered in situ during hard anodization at constant potential by modulating the flow rate of the cooling electrolyte. The pores, which could be widened at constant etch rate in phosphoric acid, were subsequently successfully replicated by the solution-wetting method using a solution of poly(methyl methacrylate) (PMMA) and a fluorescent dye in toluene. Removal of the AAO templates in aqueous KOH yielded open nanotubes with precisely controllable outer diameters. This versatile strategy, which afforded polymeric nanotubes corresponding accurately to the advanced AAO templates with radii of curvature along the nanostructures between 296 ± 13 nm and 121 ± 11 nm, can be expanded to the fabrication of unprecedented functional nanoobjects, such as nanotubes and nanorods, of a broad range of materials.