Hole burning and fluorescence spectroscopy are applied to a synthetic chlorophyll dimer, an antenna system from the bacterium Prosthecochloris aestuarii and a reaction center from the bacterium Rhodobacter sphaeroides. Information concerning the strength of the linear electron-phonon (exciton-phonon) coupling, inhomogeneous broadening, energy transfer times, nature or structure of the excited states ( S[subscript]1), the excited state decay times and the vibrational levels of S[subscript]1 for these three systems are reported and discussed. A theory for modelling the hole shape and absorption profile for a single transition which is inhomogeneously broadened and coupled to two low frequency modes, with arbitrary coupling strength, is presented and applied to photochemical hole spectra and the absorption profile of the bacterial RC from Rhodobacter sphaeroides.