We introduce a categorical analogue of Saito's notion of primitive forms. For the category of matrix factorizations of An singularity, we prove that there exists a unique, up to non-zero constant, categorical primitive form. The corresponding genus zero categorical Gromov-Witten invariants are shown to match with the invariants defined through geometric unfolding of singularities. This is joint work with Caldararu and Tu. Speaker(s): Si Li (Tsinghua University)