Ag(I) is used to form a pi-stacked metal- organic solid that exhibits remarkably high electrical conductivity. The solid undergoes a single-crystal-to-single-crystal [2+2] photodimerization to generate a 1D coordination polymer with over 40% higher conductivity. The Ag(I) complex represents the first example of an increase in conductivity resulting from a [2+2] photodimerization. Density of states calculations show a higher contribution from Ag(I) ions to the valence band in the photodimerized solid, supporting the increase in conductivity.