Abstract: I will describe a class of four dimensional field theories constructed by quotienting ordinary N=4 U(N) SYM by particular combinations of R-symmetry and SL(2,Z) automorphisms. These theories appear naturally on the worldvolume of D3 branes probing terminal singularities in F-theory, where they can be thought of as non-perturbative generalizations of the O3 plane. I will focus on cases preserving only 12 supercharges, where the quotient gives rise to theories with coupling fixed at a value of order one. These constructions possess an unconventional large N limit described by a non-trivial F-theory fibration with base AdS5×(S5/Zk). Upon reduction on a circle the N=3 theories flow to N=6 ABJM theories.