Rules of Nucleophilic Additions to Zigzag Nanographene Diones**

Nucleophilic addition of carbon-centered nucleophiles to nanographene ketones represents a valuable late-stage method for the functionalization zigzag nanographenes, but its use is rare in chemical literature. Using two model systems, non-Kekulé triangulene-4,8-dione and Kekulé anthanthrone, we identify unexpected regioselectivities uncover rules that govern these reactions. Considering large number have been reported since pioneering work Eric Clar, this enables synthesis exploration hitherto unknown functionalized nanographenes.