This cluster of papers focuses on the measurement, prediction, and modeling of diffusion coefficients of various organic compounds in liquid systems, including aqueous solutions and binary mixtures. The studies cover a wide range of solutes, solvents, and temperatures, and explore factors such as molecular diffusivity, solute-solvent interactions, and the effects of hydrogen bonding. Techniques such as Raman spectroscopy and neural network models are employed to investigate diffusion behavior in different liquid environments.