After earning her doctorate, Crassous moved to ETH Zurich, where she joined the research group of François Diederich investigating the chirality of fullerenes.
She returned to École normale supérieure de Lyon in 1998, where she worked with Laure Guy and Jean-Pierre Dutasta optical properties of chiral molecules.
[2] In 2005, she moved to the Institut des Sciences Chimiques de Rennes, where she joined the research group of Régis Réau.
[3] She has investigated the stereochemistry of a range of small molecules, including fullerenes, helicenes and organometallic complexes.
[4] In 2020 Crassous became the coordinator of HEL4CHIROLED, a collaborative international programme that looks to develop efficient organic light-emitting diodes from chiral materials.