This chapter describes a miniature nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) platform with a customized high-voltage (HV) application-specific integrated circuit (ASIC) in a 180-nm silicon-on-insulator (SOI) process. To synthesize different advanced excitation sequences to support multi-nuclei MRI, it features a multi-phase generator with phase interpolation (PI) for synthesizing composite pulses with a 0.7° phase resolution. In addition, to withstand the high-voltage stress on the front-end low-noise receiver from the NMR coil without utilizing off-chip switches, we integrate on-chip HV switches to protect the receiver during the excitation and shorten the NMR signal path to reduce the noise coupled by the conductor during the acquisition. The proposed multi-nuclei NMR/MRI platform features a 4.1-mm2 ASIC. It attains an image resolution of 173 × 250 × 103 μm3 with a 42.6-dB signal-to-noise ratio (SNR). Meanwhile, we exhibit tracking of perfluorocarbons (PFCs)-labeled porcine samples from the 1 H/ 19 F MRI results acquired by the proposed prototype.