The Schultz group investigates the composition, structure, and reactions of molecules with short-pulse laser spectroscopy. Time-resolved experiments reveal the nuclear and electronic motions that we usually hide with the chemical reaction arrow in chemical equations. A novel multi-pulse experiment (Correlated Rotational Alignment Spectroscopy, CRASY) correlates photochemical and photophysical reactions with molecular structure. The combined information reveals how changes in chemical bonding and non-covalent interactions affect chemical reaction pathways. Biochemical systems are studies to identify how a local biological environment controls the outcome of biochemical reactions. The CRASY experiments offer a fundamentally new tool to investigate heterogeneous (impure) samples. This is exploited for the investigation of tautomeric samples, molecular isotopologues, and instable molecular matter.