The global market for in vitro diagnosis is expanding in both developed and developing countries ascribed to the growing population and longer life expectancy. Conventional benchtop diagnostic tools are costly, bulky, time-consuming, and require trained technicians for operation, which confound their usages in centralized laboratory. Complementary metal-oxide semiconductor (CMOS) is a promising alternative solution for rapid and quantitative diagnosis at low cost. In addition, Nuclear Magnetic Resonance (NMR) is a trail-blazing sensing mechanism attributed to its minimal requirement on sample and hardware preparation. Significant efforts have been endeavoring to integrate the NMR system to portable scale with the aid of CMOS chips. This thesis reveals the implementation of two micro-NMR systems based on CMOS chips. The first one is a 20-MHz micro-NMR transceiver featuring a Butterflycoil input for chemical/biological assays. It enables integration with a twodimensional multi-electrode digital microfluidic device inside a space-limited portable magnet (0.46 T, 1.25 kg), making multi-sample management compatible with micro-NMR measurements, and supporting electronic automation. The transceiver occupies a die area of 2.1 mm2 , consumes 6.6/23.7 mW of power in the transmitting/receiving mode, and demonstrates the feasibility of electronic-automated biological (avidin) and chemical (CuSO4) assays achieving a detection limit on avidin of 0.2 pmol. Another prototype is a handheld micro-NMR platform with a magnetic field stabilization module. This module, composed of a current-mode vertical Hall sensor and a low-noise readout circuit, facilitates closed-loop magnetic field stabilization (2 mT  0.15 mT), which otherwise fluctuates with temperature or iv sample displacement. Together with a dynamic magnetic field transceiver and an on-chip planar coil for micro-NMR assay and thermal control, the system demonstrates: 1) selective biological targets pinpointing (<100 pM from a 2.5-μL sample of Enterococcus faecalis derived DNA); 2) protein state analysis and 3) solvent-polymer dynamics, suitable for healthcare, food and colloidal applications, respectively. Compared with a commercial NMR-assay product (Bruker mq-20), this platform greatly reduces the weight (96x), hardware volume (175x) and sample consumption for the assay (120x).