Pressure tuning spectroscopy has proved to be a powerful tool for characterizing electronic excitations, testing theories, and inducing electronic transitions of both scientific and technological significance. In this brief paper we outline two studies involving luminescence of molecules dissolved in solid polymers: (1) Two-photon excitation is a process of importance in the operation of many useful lasers. From our pressure study of Rhodamine B in poly(acrylic acid), we characterize the differences between the paths for one- and two-photon excitation. (2) Some molecules can assume two different geometries in the excited state and have potential as switching devices. We test a model for the processes involved by showing that the change of the steady-state emission intensity as a function of pressure can be predicted from time-dependent data.