This is a standalone program for a) the calculation of diffusion coefficients of sorbates inside nanoporous materials at different loadings by using transition rate constants and for b) solving the master equation for a system consisted of a large number of unit cells per each direction. It is based on the following published paper "Kolokathis, P. D., Braun, O. M.. J. Comput. Chem. 2019, 40, 2053– 2066. DOI: 10.1002/jcc.25857"