We have developed a simple, direct and scalable method for anti-Friedel-Crafts alkylation of electron poor aromatics by exploiting the photolytic fragmentation of an electron donoracceptor (EDA) complex propagated through radical anion autocatalysis. This autocatalytic mechanism is strongly supported by DFT computation and kinetic evidence, which both demonstrate an increasing reaction rate and an accelerated reaction upon addition of an auxiliary base. Our strategy enables regioselective, photocatalyst-free C-H alkylation using only inexpensive, readily available and non-toxic catalysts. Notably, the catalytic fragmentation of the EDA complex eliminates the need for any exogenous oxidants or reductants.