Infrared spectroscopy
Marvel worked with a wide variety of compounds, including dialkyl mercury, hexa-substituted ethanes, dienynes, alkyl lithium and Grignard reagents, quaternary phosphonium, and ammonium compounds, preparing them and investigating their reactions. He developed organic chemical reagents to be used in the characterization, identification, and analysis of chemical compounds. Much of this research was carried out before techniques such as Infrared spectroscopy or Mass spectrometry were developed: for example, Marvel's exploration of intermolecular hydrogen bonding relied on studying solubilities and heats of mixing.