Mobius pi-conjugation in cyclic molecules leads to the reversal of Huckel aromaticity rules and affects the electronic and magnetic properties of these systems. We found the first example of a medium-sized macrocyclic structure that is sufficiently flexible to switch between three distinct pi-conjugation topologies, planar (T0), Mobius (T1), and twisted Hockel (T2), without changing its oxidation level. The switching is under thermodynamic and kinetic control and can be realized in a three- or four-step cycle. On titration with trifluoroacetic acid (TFAH) or dichloroacetic acid (DCAH), the Mobius free base (T1-H-2), which is the preferred structure in dichlorofluoromethane at 150 K, undergoes a series of acid-base reactions involving changes of the pi-conjugation topology. The forms observed in the course of titration involve a Mobius aromatic monocation ([T1-H-3](+)), an antiaromatic twisted Huckel species ([T2-H-4(A)](+)) containing a coordinated carboxylate anion (A = TFA, DCA), and two additional M6bius forms ([T1-H-4(A)(HA)(n)](+) (n = 1, 2)), containing complex carboxylate anions. The protonated forms undergo a thermally activated ring planarization to yield an antiaromatic quasi-planar dication [T0-H-4](2+), characterized in the solid state as a TFA salt. The corresponding free base (T0-H-2) is metastable but can be trapped by addition of triethylamine at low temperatures.