New compounds of the general formulas [M(Ar-BIAN)2]BF 4 and [M(Ar-BIAN)(NCMe)2]BF4, where M = Cu I or AgI and Ar-BIAN = bis(aryl) acenaphthenequinonediimine, were synthesized by the direct reaction of [Cu(NCMe)4]BF4 or [Ag(NCMe)4]BF4 with the corresponding Ar-BIAN ligand in dried CH2Cl2. The synthesized compounds are [M(o,ó,p-Me3C6H 2-BIAN)2]BF4 where M = CuI (1) and AgI (2), [M(o,ó-iPr2C6H 3-BIAN)(NCMe)2]BF4 where M = CuI (3) and AgI (4), and [Ag(o,ó-iPr2C6H 3-BIAN)2]BF4 (5). The crystal structures of compounds 1-3 and 5 were solved by single-crystal X-ray diffraction. In all cases copper(I) or silver(I) are in a distorted tetrahedron that is constructed from the four nitrogen atoms of the two α-diimine ligands or, in 3, from one α-diimine ligand and two acetonitrile molecules. All compounds were characterized by elemental analyses, matrix-assisted laser desorption-ionization time-of-flight mass spectrometry, and IR, UV-vis, and 1H NMR spectroscopy. The analysis of the molecular geometry and the energetic changes for the formation reactions of the complexes, in a CH2Cl2 solution, were evaluated by density functional theory calculations and compared with the experimental results.