By-products derived from the distillation of medicinal and aromatic plants (MAPs) following the principles of a circular, sustainable, and ecological economy, may be regarded as a valuable resource for various applications. Α novel operational approach to retrieve bioactive compounds from solid by-products of MAPs that remain post-processing is presented in this study. The utilization of nanoencapsulation technology is proposed to enhance the bioactivity of the recovered compounds at minimal extract concentrations by encapsulating them, aiming at the development of environmentally friendly nanotechnology suitable for various food applications. A total of four specific MAPs, generating by-products post-distillation and/or post-harvesting, were examined: Saffron (Crocus sativus) petals, Chamomile (Matricaria chamomilla), Golden Root (Rhodiola rosea) aerial parts, and Lavender (Lavandula angustifolia vera). Best-practice technologies are being disseminated, with research focusing on emerging developments in recovery techniques as well as on the nanotechnological application of the bioactive compounds or mixtures. Upon the completion of the production of plant by-product materials, the subsequent stage will involve the collection and stabilization of a specific biomass. Various emerging drying technologies, including vacuum, microwave, and freeze-drying systems, will be evaluated through experimental and parametric analysis. Extraction methods for bioactive compounds will encompass the use of supercritical fluid extraction, microwave-assisted extraction, ultrasonic-assisted extraction, and deep eutectic solvents extraction, while for extraction and subsequent purification and fractionation, preparative column chromatography may be employed as well. The metabolite profiles of specific plant by-products will undergo analysis using hyphenated techniques like UPLC-DAD-MS/MS, GC-MS/MS, and conventional phytochemical approaches to identify main and minor components in the obtained fractions.