  We compute three-point functions of general operators in the su(1|1) sector
of planar N = 4 SYM in the weak coupling regime, both at tree-level and
one-loop. Each operator is represented by a closed spin chain Bethe state
characterized by a set of momenta parameterizing the fermionic excitations. At
one-loop, we calculate both the two-loop Bethe eigenstates and the relevant
Feynman diagrams for the three-point functions within our setup. The final
expression for the structure constants is surprisingly simple and hints at a
possible form factor based approach yet to be unveiled.
