The photo-modulation of molecular motions have already been investigated with overcrowdedalkene-based systems, 10,27,28 azobenzenes 29 and diarylethenes, as examples. Herein, inspired by the elegant work of Hashimoto et al., on the photo-modulation of the excimeric emission of pyrene, we report the new pyrene-based DTE 1o (Figure ). In 1o, the two pyrenes can face each other in the open's DTE form, thus leading to static excimer emission. Upon ring-closure reaction, the pyrene introduced on the inner position will be moved apart from the lateral pyrene, thus avoiding the possibility of excimer. To benefit from a large molecular movement upon photocyclization the DTE must be functionalized at the lateral and internal positions, as the changes in distance between the two lateral positions upon photochromism is only 1 Å. However, reports on DTEs functionalized at the lateral and internal positions are rare due to the synthetic challenge that represents such an unsymmetrical functionalization. Thus, design of 1o is expected to give higher propensity of excimer emission in comparison to a symmetrically substituted DTE. Nonlinear optical processes such as stepwise and simultaneous two-photon excitation (TPE) have been reported to enhanced the cyclo-reversion reaction of DTE. However, for both TPE processes, the photo-cyclization reaction is known to be ineffective. Knowing that TPE produces specific one-photon forbidden excited states, the combination of one-and two-photon excitations can allow to selectively trigger the photochromism and collect the excimer emission in 1o, respectively. This opens the way of an unprecedented non-destructive fluorescence readout with orthogonal light stimuli i.e.; one-photon irradiation (UV and visible) employed to control the photochromic reaction and two-photon excitation (730 nm) used to probe the fluorescence.