A new niobium oxyfluoride, Nb2O2F3, synthesized through the reaction of Nb, SnO, and SnF2 in Sn flux, within welded Nb containers, crystallizes in a monoclinic structure (space group: I2/a; a = 5.7048(1)angstrom, b = 5.1610(1)angstrom, c = 12.2285(2)angstrom, beta = 95.751(1)degrees). It features [Nb2X10] units (X = O, F), with short (2.5739(1) angstrom) NbNb bonds, that are linked through shared O/F vertices to form a 3D structure configurationally isotypic to zeta-Nb2O5. Nb2O2F3 undergoes a structural transition at similar to 90 K to a triclinic structure (space group: P1(-); a = 5.1791(5)angstrom, b = 5.7043(6)angstrom, c = 6.8911(7)angstrom, alpha = 108.669(3)degrees, beta = 109.922(2)degrees, gamma = 90.332(3)degrees). The transition is described as a disproportionation or charge ordering of [Nb-2](7)+ dimers: (2[Nb-2]7+ -> [Nb-2](6)+ + [Nb-2](8)+), resulting in doubly (2.5000(9) angstrom) and singly bonded (2.6560(9) angstrom) Nb-2 dimers. The structural transition is accompanied by an unusual field-independent spin-gap-like magnetic transition.