The corresponding monofunctionalization, using either 17 or 20, was not successful (Scheme 2d). Although the desired product (27) was detected in both cases (by LC-MS) during the reaction along with considerable amount of dehalogenated starting material, following the work-up it disappeared from the mixture. From the cross-coupling attempts it seems that the monofunctionalized products are challenging substrates due to comparably low stability in most of the cases. In these derivatives the remaining two reactive positions in the carbocyclic ring could be responsible for the decomposition. It is likely that protecting these positions will lead to further stable derivatives. In summary, we synthesized 1,3-bis(dimethylamino)-2azapentalene 3 and characterized its structure and basic opto-electronic properties using both experimental techniques ( 1 H NMR, X-ray crystallography, UV-vis spectroscopy) and computed aromaticity indices (NICS, ACID, HOMA). These revealed that the donor NMe2 groups have a key role in stabilizing the azapentalene π-system that otherwise has an antiaromatic character. Due to this electron donation the heterocyclic ring of 3 become relatively electron poor, while its carbocyclic ring relatively electron rich that is also reflected in its reactivity, which we explored through model reactions. These included the reproduction and optimization of some previously reported transformations such as formylation and amine substitution, and also the expansion of the previously known scope of reactions with azo-coupling, selective halogenations and cross coupling reactions. In future research we plan to further expand the scope of stable derivatives of 3 and to incorporate it into π-extended frameworks and photoresponsive structures.