Electron transfer (ET) quenching of duroquinone (DQ) triplet by triphenylamine (TPA) coadsorbed onto porous silicas with different average pore size (PS = 2.2, 4, 6, 14, and 100 nm) and back ET within corresponding geminate triplet radical ion pairs (RIPs) were studied at different temperatures by the diffuse-reflectance laser flash photolysis technique. The PS effects both on inter- and intracage molecular dynamics and on the distribution of adsorbed molecules are discussed in terms of fractal effects in restricted geometries. The PS effect on the static ET quenching of (3)DQ by TPA (responsible for fast (less than or equal to 10 ns) formation of RIPs) is well described by the Perrin model in appropriate fractal dimensions, df. The values of dr ranging from 3 to 2.37 are PS dependent in a manner similar to that known for long-range Forster type energy transfer. The average and time-dependent behavior of kinetics of diffusion-controlled dynamic quenching of (3)DQ by TPA and that of back geminate ET both are strongly dependent on the surface irregularity. The decrease of PS results in significant increase in kinetics heterogeneity (decrease in value of spectral fractal dimension, d(s), from 1.7 to 1 equivalent to a bimolecular reaction in one dimension) and in decrease in the average rate constants of dynamic quenching. The dynamic quenching reaction is characterized by apparent high values of activation energies which decrease with PS from 8.5 to 4.6 kcal/mol. However, the accompanied 4 orders of magnitude decrease in preexponential terms seems to be the most important factor. It is concluded that molecular mobility is faster on small PS silicas, sind the effect of irregularity dominates for diffusion-controlled reactions. The pronounced supercage effect accompanied by a strong magnetic field effect (MFE) was observed for back geminate ET on silicas with small PS, where the imposition of external magnetic field 0.05 T leads to up to 3 times retardation of geminate recombination.