Recent advances in the use of the concept of the Thorpe–Ingold effect to rationalise some synthetic chemistry involving organosilicon compounds and, in particular, the photophysical properties of certain dialkylsilylene spaced conjugated chromophores are discussed. The silicon moieties are considered to be insulating tetrahedral spacers in these silicon-containing copolymers. The substituents on silicon can readily be tuned and the steric environment of these substituents around the silicon may dictate the conformation (or helicity) of the copolymers and hence their photophysical properties. This substituent effect on silicon can be understood by the concept of the Thorpe–Ingold effect.