IN THE STRUCTURE OF THE TITLE COMPOUND [SYSTEMATIC NAME: 1-(naphthalen-2-yl)ethanone], C(12)H(10)O, the acetyl group is approximately coplanar with the naphthalene ring with a C(ar)-C(ar)-C=O torsion angle of 5.8 (2)°. In the crystal, the mol-ecules are packed in a classic herringbone arrangement typical for aromatic polycycles such as penta-cene. They are also linked by weak end-to-end C-H⋯O interactions along the ac diagonal.