Concept and Nomenclature A MMP is formed by two compounds that di↵er from each other by a defined change at one or more specified positions. The point where the change takes place is referred to as the attachment point; the local environment of an attachment point is denoted as the context, or simply the environment. The part of the molecules that is identical is called constant, and the part that changes is named the variable. Consequently, the compounds belonging to a MMP can be converted to one another by the molecular transformation of variable A to variable B, i. e. A ! B. Transformation types include, for instance, additions (H ! X) or functional group replacements (e. g., Cl ! OMe) or linker/sca↵old exchange. Every transformation is associated with a relative change in a property value in general ( P), here a change in the lyso score. Subsequently, the same transformations are grouped together and the statistics of the property changes are calculated (frequency of occurrence, P distribution, average P, etc.), which collectively yields the rules. Taken together, examination of analogous compounds can determine the contribution of each substituent or structural element to the overall property of the compound (assumption of additivity). 48 Furthermore, it is anticipated that the e↵ect of a substituent on the respective physicochemical/biological property can be generalized, i. e. that its contribution is transferable across compound series. Given that the method captures the implicit knowledge contained in the chemical dataset in a systematic and automated manner, the emergence of the rules is fully explainable (as it is easy to trace back to the underlying compound pairs), resembles the intuitive way of a chemist's thinking, and lacks the "black box" character, which is frequently raised as a point of critique concerning machine learning or other in silico methods utilized for (Q)SAR analysis. The MMP concept has been widely employed. However, to the best of our knowledge, the application of this approach to a CP data set and with a view to lysosomotropism has not been reported to date.