The quenching of photoexcited porphyrins by porphyrin cation radicals at adjacent or distant sites in diphenylethyne-linked porphyrin dyads and triads has been studied using static and time-resolved optical spectroscopy. The excited-state quenching is highly efficient in all cases (> 99%) and occurs in less than or equal to 11 ps between adjacent sites (by through-bond energy/charge transfer) and in less than or equal to 55 ps between distant sites (likely by superexchange-assisted energy transfer). The rates can be tuned using the porphyrin-linker connection motif. These results should prove useful in the design of arrays that use electro- or photo-chemically generated porphyrin cation radicals for molecular switching and other applications in molecular photonics.