Synthetic polymers belong to the vast realm of soft matter and are one of the key types of materials to address societal needs at the beginning of the twenty-first century. Polymer science progressively addresses questions that deal with tuning mesoscopic and macroscopic structures and functions of polymers by understanding the effects that govern these systems on the nanoscopic level. EPR spectroscopy as a local, sensitive, and extremely specific magnetic resonance technique in many cases shows sensitivity on well-suited length- (0-10 nm) and time scales (μs-ps) and can deliver unique information on structure, dynamics, and in particular function of polymeric systems. A short review of recent literature is given and the power of simple EPR methods, especially CW EPR performed on a low-cost benchtop spectrometer, to elucidate complex polymeric materials is shown with specific examples from thermoresponsive polymer systems. These bear great potential in molecular transport and biomedical applications (e.g., drug delivery) and insights into interactions between carrier and small molecule are fundamental for designing and tuning these materials.