Recently Sagmeister et al. assembled four complementary PAT including inline NMR, UV/Vis, IR, and online UHPLC, to meticulously monitor the intricate three-step linear synthesis of the mesalazine drug (Figure ) with a 1.6 g h -1 throughput. In the first step, the nitration reaction was monitored by inline NMR. The overlapping peaks were resolved for accurate quantification by building a chemometric model. The model also allowed for flexibility to small changes in peak positions and shapes in repetitive analysis. An in-house designed flow cell equipped with a reflectance probe was employed for real-time monitoring of hydrolysis by inline UV-Vis spectroscopy. The raw data were processed using a sophisticated neural network (NN) algorithm, yielding rapid quantification with an impressive processing time of 1.4 ms per spectrum. This streamlined approach ensured efficient and timely data analysis, facilitating seamless real-time monitoring of the hydrolysis of 16. The final step hydrogenation progress was monitoroted by inline IR probe. The spectral data was processed using a partial least squares (PLS) regression model and quantified. An online ultra-high performance liquid chromatography (UHPLC) was used to analyze the final composition of the reaction mixture after three reaction steps. The integration of all the PAT tools into the three-step reaction was carefully executed with an open platform communication unified architecture (OPCUA) platform for inter-platform equipment communication. The adoption of the OPCUA platform, ensured seamless communication among different equipment platforms for enhanced efficiency and accuracy in data analysis.