NMR offers a plethora of tools for investigating several tissue properties in vivo. The present talk aims at describing novel MRI and MRS approaches that have been recently developed in our laboratory, based on the implementation of frequency swept pulses in the adiabatic and sub-adiabatic regimes1-6 . The contrasts generated by such techniques will be explained within the context of rotating frame relaxation mechanisms5,6 , magnetization transfer effects4 , relaxation along a fictitious field (RAFF)3, and MRI without the formation of an echo2. Frequency swept pulses offer unique capabilities to investigate biological systems for both in vivo and high-resolution NMR. Applications to functional MRI, to brain imaging of diseases like Multiple Sclerosis and Parkinson diseases7, and to quantification of protein dynamics8 will be presented.