Figure . Employing crystal engineering to tune excitonic coupling in chromophoric SURMOFs using steric control units (SCUs). (a) Without SCUs, the naphthalene-diimide (NDI) linkers yield a non-luminescent assembly (H-aggregate). A theoretical analysis revealed that increasing the angle Q controlling the stacking of the linkers (b) modifies the coupling such that luminescence is recovered. (c) The workflow used to screen the library of possible linkers is indicated in the lower left. (d) TDM-TDM coupling changes sign (TDMtransition dipole moment). Figure adapted from Ref. [117].