Models of open non-isothermal heterogeneous reaction systems can be quite complex as they include information regarding the reactions, the inlet and outlet flows, the transfer of species between phases and the transfer of energy. This paper builds on the concept of reaction variants and invariants and proposes a linear transformation that allows viewing a complex nonlinear reaction system via decoupled dynamic variables, each one associated with a particular phenomenon such as a single chemical reaction, a specific mass transfer or heat transfer. Three aspects are discussed, namely, (i) the decoupling of reaction and transport phenomena in open non-isothermal both homogeneous and heterogeneous reactors, (ii) the decoupling of spatially distributed systems such as tubular reactors, and (iii) the applicability of the decoupling transformation towards the analysis of complex reaction systems, in particular with respect to the analysis of measured data in the absence of a kinetic model.