The ability to probe the smallest building blocks of matter has long fascinated scientists, fueling advancements in medicine, security, and materials science. Traditional methods like nuclear quadrupolar resonance (NQR) spectroscopy have revealed molecular structures by detecting interactions between nuclear quadrupole moments and local electric field gradients. Despite their utility, these techniques are fundamentally limited by their reliance on macroscopic ensembles of nuclei. This limitation masks the molecule-to-molecule variations critical in fields such as protein research or drug development. Recent breakthroughs at the University of Pennsylvania’s School of Engineering and Applied Science (Penn Engineering) have overcome these limitations. Using quantum sensors embedded in diamonds, researchers have refined NQR spectroscopy to detect signals from individual nuclei—a feat previously deemed impossible. This advancement opens the door to transformative discoveries in molecular science. Traditional NQR spectroscopy employs radio waves to identify molecular “fingerprints,” making it a staple in detecting explosives, analyzing pharmaceuticals, and conducting thermometric studies. These methods, however, average signals across trillions of atoms, overlooking subtle but significant molecular differences. In protein research, for example, small structural variations …