The intramolecular electronic excitation coherence created by the first femtosecond laser pulse in a linked-anthracene dimer, dithia-1,5[3,3]-anthracenophane (DTA), was enhanced or depreciated by the interference with the second femtosecond laser pulse, which is phase-locked to the first pulse. Two anthracene rings in DTA are stacked parallel but with nearly orthogonal orientation. The interference intensity of fluorescence from DTA was measured as a function of delay time between two pulses with the optical phase angle being fixed with 0degrees (in-phase) or 180degrees (anti-phase). Two components of enhanced and depreciated oscillations appeared in the subpicosecond region as a function of the delay time, with the time periods depending on the excitation wavelength. On the basis of theoretical analysis, the two components were assigned to the sum and difference frequencies between the energy splitting of molecular eigenstates and the detuning of the laser frequency relative to the molecular electronic transition energy. The exciton splitting between the two superposition states of the local excitation was derived to be 2beta = 35 cm(-1), which is in close agreement with our previous result (29 cm(-1)) obtained from fluorescence anisotropy decay measurement.