Hyperpolarization can increase the sensitivity of NMR/MRI experiments, but the primary limitation is the T, decay of magnetization. Due to its long T-1, the hyperpolarized Y-89 nucleus makes an excellent candidate as an in vivo spectroscopy/imaging probe. Here we report the Y-89 chemical shift dependence upon pH for two hyperpolarized Y-89(III) complexes and demonstrate how such complexes can be used as sensitive spectroscopy/imaging agents to measure pH.