Two-photon polymerization (2PP) is a leading high-resolution light-based additive manufacturing technique, enabling three-dimensional structures with sub-micrometer features. However, its serial, voxel-by-voxel scanning imposes a fundamental volume-speed constraint: high resolution requires tight focusing and small voxels, which drastically limits throughput and confines 2PP to small build volumes. At sub-micrometer resolution (~150 nm lateral, ~1 µm axial voxels), a 1 mm^3 volume contains 4.4x10^10 voxels, requiring a ~6.7 km scan path. Even with commercial systems reaching 250 mm/s and continuous motion, fabrication takes a minimum of ~7.4 hours; accounting for galvanometric mirror acceleration and deceleration at each line reversal, the actual time rises to over 12 hours. As fabrication time scales inversely with voxel volume, printing the same structure at 100 nm resolution takes roughly 10^3 times longer than at 1 µm resolution, fundamentally restricting 2PP to small build volumes when sub-micrometer fidelity is required. Increasing volumetric fabrication speed without sacrificing sub-micrometer resolution remains a central open challenge in the field. Before addressing this speed-resolution trade-off, I first develop and validate a custom-built 2PP printer by establishing 2PP as a viable tool for high-performance polyimides. I demonstrate high-aspect-ratio 3D structures with sub-micrometer feature sizes and show that thermal imidization at 200 °C and subsequent carbonization at temperatures up to 1600 °C yield conductive carbonaceous microstructures with electrical conductivities of 1.4x10^2 S/m, confirmed by Raman spectroscopy and transmission electron microscopy (TEM) as exhibiting pronounced graphitic order. This is the first report of sub-micrometer 2PP-printed all-aromatic polyimides and their conversion to conductive carbon, extending the material scope of high-resolution 3D printing and demonstrating the custom platform's ease of use and versatility. Building on this platform, this dissertation investigates single-photon-assisted strategies to address the volumetric fabrication speed of 2PP using two complementary directions. First, a single-photon pre-sensitization strategy is demonstrated, in which blue-light pre-sensitization in a light-sheet configuration, integrated into the custom-built 2PP printer, reduces the required femtosecond laser power for polymerization by a quarter and halves the exposure time compared with polymerization driven only by two-photon absorption, while also improving axial resolution. Presensitizing the photoinitiator prior to two-photon exposure shifts the polymerization onset to a lower infrared dose. A theoretical model is developed, suggesting that the presensitization mechanism is driven by oxygen depletion followed by single-photon background latent polymerization. Second, the single-photon and two-photon modalities are integrated into a unified multiscale printing platform, combining single-photon Tomographic Volumetric Additive Manufacturing (TVAM) with 2PP in a single setup using the same photoresin. TVAM fabricates millimeter-scale volumetric structures within seconds, after which 2PP writes sub-micrometer features both on the surface and embedded within the pre-polymerized volume. This hybrid platform spans three orders of magnitude in scale within a single, uninterrupted workflow, demonstrating a route toward multi-scale high-speed, high-resolution 3D fabrication.