Single molecule spectroscopy has tremendously impacted every field in which the technique was applied, ranging from catalysis over plasmonics, polymer physics, biophysics to cell biology and DNA sequencing. Furthermore, single molecule techniques have allowed researchers to push the resolution of fluorescence microscopy past the diffraction limit. In this presentation, I will give an overview of how recent single molecule experiments and development of new microscopy modalities in my laboratory have resulted in research in optical mapping, optical trapping and expansion microscopy.