In the title compound, C16H11ClN2O2, the 2-methyl-1,3-dioxoindan-2-yl and 4-chlorophenyl groups are trans to each other. The five-membered ring of the indandione moiety adopts an envelope conformation. The phenyl and azo groups are not coplanar because of steric hindrance between the lone-pair orbitals on the carbonyl O atom and beta-N atom [C-N=N = 112.4 (3)-degrees]
