Application of this iron-catalyzed AAPE reaction on conjugated ketones that are easily available as either organic semiconductors or pigments to construct new conjugated skeletons for developing electronic materials are certainly attractive. We decided to test this possibility on pentacene-6,13-dione, a precursor for synthesizing pentacene 34 and also the product of pentacene oxidation , to provide pentacene-π-extended aza-arene. The five linearly fused benzene ring resulted in elevated HOMO level, making the conjugated molecule sensitive towards to chemical oxidant. The large p-conjugation also increases propensity of π-coordination toward a transition metal thus inhibiting desired reactivity of a transition metal catalyst. To our delight, reaction of oxime ether derived from pentacene-6,13-dione afforded anthra[1,2,3,4-lmn]benzo[f] [2,9]phenanthroline (abbreviated as ABPhen, 34) as a single product 5 quantitatively (Figure ). The possible regioisomer of benzo [5,6]isoquinolino [1,8-gh]naphtho[1,2,3de]quinoline was not formed. The selectivity of the CH sites for the second cyclization could be explained by the acidity of C-H bonds that determines the rate of deprotonative C-H cleavage. The reaction was easily scaled up to a gram scale yielding 1.23 g of 34 in 79% yield after recrystallization (Figure ). The structure of 34 was unambiguously proved by single crystal X-ray analysis, showing an unprecedented 10 conjugation framework. In sharp contrast to our Fe/Al catalytic system that provided 34 in quantitative yield, the other literature conditions for similar cyclization of oxime or oxime ether employing other metal catalysts such as Co 39 , Mn 40 , Ru 41 , Ir , and Rh 43 , all failed to react. Only one feasible condition was a rhodium-catalyzed condition elegantly developed by You and co-workers , while 20 mol % of rhodium was used with only a moderate yield obtained. 15 A distinct separation of frontier molecular orbitals was revealed by the calculations. Unlike traditional pentacene structure and derivatives, the integration of imine moiety as electron-accepting units in ABPhen (34), where the LUMOs locate (Figure ), fosters enhanced localization of electron density.