In the context of IIoT (industrial internet of things) or I40 (Industry 4.0), PAT is established now in industry as an enabling technology to control and monitor processes at the molecular level. Sensors based on optical spectroscopy can be used to record the chemical structure of molecules using the absorption spectra. In the case of opaque systems even the nanoscopic morphology of particles, cells or tissues can simultaneously be measured by their complex spectra of the elastic light scattering (ELS) features. To fully exploit these two fundamental information different strategies can be applied. This review starts with examples of single particle analysis resp. particle aggregates classification using optical spectroscopy at shorter wavelengths to demonstrate the power of ELS. Complex morphological structures of chromosomes or tissues can fast and accurately be classified using hyperspectral imaging technology. When multiple methods are used, e.g., the combination of Raman and UV-Vis-spectroscopy, multimodal optical spectroscopy offers several advantages, particularly when examining and characterizing biological materials with markers at low concentrations. The major advantage of using NIR spectroscopy instead of multimodal spectroscopy is however, that both, absorption and scattering spectra can be measured simultaneously with a single device. This feature saves time and costs especially in PAT applications. The purpose of this presentation is to demonstrate to the reader the potential of inline spectroscopy for the chemical and morphological characterization of materials through various examples.