Quantum yield of photoisomerization of degassed n-hexane solution of all-trans-retinal (1) and all-trans-1, 4-diphenylbutadiene (4) at 25$circ$C under direct irradiation conditions increases as the concentrations of 1 and 4 increase. Further, fluorescence lifetime of 4 at ambient temperature is also found to increase as the concentrations of 4 are increased. The results are discussed in terms quantum chain process which occurs due to exchange of energy between various conformers of the compounds concerned.