Intermolecular photoprocesses in glassy solutions of magnesium octaethylporphine (MgOEP) and zinc tetrabenzoporphine (ZnTBP) have been investigated under one- and two-color irradiation between 8 and 80 K. The simultaneous exposure to the pulsed laser light in resonance with the 0-0 S-1 <-- S-0 transition and the continuous blue light absorbed by the Tn <-- T-1 transitions leads to a much faster hole burning than the irradiation with the laser light alone. This photon gating effect is observed in many reactive solvent glasses or the mixtures of a reactive component and the inert diluent. In solvent glasses containing electron accepters (alkyl halogenides, tert-butyl peroxybenzoate, ethyl diazoacetate) the two-quantum photooxidation results in the bleaching of porphyrin absorption bands and formation of cation radical absorption at 650-700 nm (in the case of MgOEP). In the presence of electron donors (triethylamine) and alkenes the photoreaction can be observed only in the hole-burning regime because upon broad-band irradiation the intensity and position of the 0-0 band remain unchanged. The hole burning in these systems stems from sensitized photoprocesses leading to the rearrangement of pigment environment. The microscopic solvent shift of the zero-phonon transition frequency of the pigment following cis-trans isomerization of the alkene molecules or reversible electron transfer results in the formation of a dip in absorption. In this case "antiholes" are observed as a result of intensity redistribution within the 0-0 band. Depending on the height of the triplet level of the alkene, the sensitization can take place by means of tripler energy transfer from either the T-n or T-1 state (to cyclooctatetraene) of the pigment. The influence of concentration, chemical structure, reduction potential, and the height of tripler energy level of activators as well as the matrix properties on the efficiency of gated hole burning has been investigated. The reactivities of aliphatic halocarbons and amines, aromatic electron accepters and donors, cyclic and linear olefins with and without electron-accepting substituents, and other compounds have been studied. The most efficient sensitizers have been selected and doped in the polymer films which are more convenient for the applications of spectral hole burning in optical data storage.