Two lithographic techniques suitable for fabricating complex 3D structures with high spatial resolution are presented and discussed. The first one is based on the combined use of nanoimprint and X-ray lithography. Its technological potential has been demonstrated by patterning several types of structures with X-ray lithography on hexagonal array of hemispheres obtained previously by nanoimprinting. These consecutive steps give rise to an intersectionstructure where the overall profile of high aspect ratio structures is enveloped by the original 3D imprinted profile. The second technique, two-photon lithography, is an intrinsic 3D lithography and has the highest potential for structuring 3D in the widest sense. The principle of this technology and experimental results in the field of nanomechanics and photonics will be presented.