One of the most important properties of molecules in the biological world is three-dimensional shape. Organisms interact with molecules based to a large extent on molecular shape. Many compounds fit together with cell-based receptors (which are themselves molecules of very particular shapes). When this happens, a biological response results: a signal to the brain, the onset of cell division, or other possibilities.
Because shape can influence how two molecules fit together, it can affect physical properties as well as biological ones. For example, if a compound is made of molecules that cannot fit together easily, London dispersion interactions are limited, and so the compound is less likely to be a solid.