After a few remarks on the history of molecular modelling we de-scribe certain mathematical aspects of the generation of molecularstructural formulae. The focus is on the automatic generation of struc-tural formulae for the purpose of molecular structure elucidation andthe examination of molecular libraries. The aim is to give a reviewand to point to relevant literature. We demonstrate an applicationin the area of quantitative structure-property/activity relationships.Then, we give a glance on ongoing research in the generation of 3D-structures (stereoisomers and conformers), and finally we mention twoproblems that should be solved in the near future, the possible use ofhypergraphs, and the generation of patent libraries.