By observing single molecules, researchers can capture sequential events, avoiding population averaging issues. Additionally, this approach reveals the conformational states and solvent environments that can affect biological function and optical spectra, particularly at low temperatures. By combining SMS with scanning probe microscopy (SPM), it is possible to measure mechanical and electrical properties, such as binding forces and conductivity [5]. A new possibility of SMS involves enhancing photon analysis capabilities, correlating information like photon arrival time, polarization, wavelength, and excited-state lifetime. Such developments help to interpret biological dynamics at the single-molecule level. Another budding technique is plasmonic nanospectroscopy, which combines spectroscopy with nanotechnology to achieve high spatial resolution and sensitivity [6]. By coupling light with surface plasmons on metallic nanostructures, the enhancement of spectroscopic signals is achieved to probe nanoscale phenomena with extraordinary precision. Applications span nanophotonics, biosensing, and materials science, allowing the study of individual nanoparticles, molecular vibrations, and surface phenomena. Techniques like surface-enhanced Raman spectroscopy (SERS) and tip-enhanced Raman spectroscopy (TERS) offer label-free, sensitive molecule detection down to the single-molecule level [7]. Plasmonic nanospectroscopy aids in biomedical diagnostics, environmental monitoring, and chemical analysis. Advancements in nanofabrication produce tailored plasmonic nanostructures, enhancing optical properties for specific applications. Integration with fluorescence and electron microscopy offers comprehensive insights into nanoscale phenomena. In summary, plasmonic nanospectroscopy is a powerful tool driving understanding and innovation across disciplines, promising new capabilities in fundamental research and applied sciences. Known for half a century, the evolution of ultrafast spectroscopy towards quantum spectroscopy hinges on the ability to manipulate quantum correlations of light, including entanglement, in light pulses of varying waveforms and intensities [8]. This crucial advancement opens avenues for exploring the direct detection and manipulation of many-body states, thus serving as a precise resource for quantum information science. Both theoretical frameworks and experimental methodologies are being developed to enable the realization of all-experimental quantum spectroscopy, particularly in semiconductor systems. This innovative technique meets the rigorous criteria for achieving direct, user-defined quantum-optical excitations of many-body states, marking a significant advancement towards harnessing the full potential of quantum spectroscopy in materials science and beyond. The evolution and expansion of spectroscopic techniques over time portray the dynamic nature of scientific inquiry and technological innovation. As research requirements evolve and new challenges emerge, spectroscopy continually adapts and advances to meet the demands of diverse fields ranging from fundamental physics to applied materials science and biomedical research. The authors acknowledge the funding from national funds (OE), through FCT--Fundacao para a Ciencia e a Tecnologia, Portugal, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of Article 23 of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. This work was developed within the scope of the project i3N, UIDB/50025/2020 and UIDP/50025/2020, financed by national funds through the FCT/MEC. The authors declare no conflicts of interest.