A phenothiazine derivative (rong class="boldFont">EPBPArong>) containing benzoyl groups was synthesized.
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rong class="boldFont">EPBPArong> showed reversible mechanofluorochromic nature.
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The single crystal structure of rong class="boldFont">EPBPArong> revealed the hydrogen bonds CHrong class="boldFont">⋯rong>C (2.864 Å), CHrong class="boldFont">⋯rong>C (2.850 Å), CHrong class="boldFont">⋯rong>O (2.652 Å).
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Mechanofluorochromic nature is generated through crystalline-amorphous phase transformation under external pressure.