Due to recent progress in synthetics, the ready obtainment of various N-substituted carbazole heterocycles opened a wide window of scientific and industrial opportunities in different R&D domains. As summarized in this review article, such attractive R&D domains concern (a) electrochemically grown functional polycarbazole films for (bio/chemo) sensing, covalent grafting of biomolecules, nanomaterial fabrication (polycarbazole-containing nanorings and dendrimers), and surface patterning/engineering (biochip fabrication), and (b) oxidatively grown materials containing a polycarbazole phase (template or non-templated liquid oxidation polymerizations). This last general approach led to numerous developments in the fabrication of various composite materials incorporating single/multiwalled carbon nanotubes, graphene oxide, and magnetic magnetite-based nanoparticles for the ultrasensitive detection of DNA hybridization for example. Some liquid-phase oxidative polymerizations of UV-sensitive carbazole-containing species also afforded corresponding polymeric UV-reactive microspheres for UV surface patterning and functionalization/structuration. All these novel polycarbazole- containing species generally possess interesting optical properties useful for sensing and photoelectronic/photovoltaic applications. In summary, the already proven rich organic chemistry and corresponding (electro/chemical) polymerization properties of such specific carbazole heterocycles are expected to generate even more wider output applications far beyond current knowledge in the field (combinatorial polymeric engineering, biocompatible medical devices/materials, for example).