Piezochromic luminescent materials with multi-color switching have recently attracted much attention owing to their appealing applications in the field of advanced photonics, such as optical recording, memory and sensors. Mechanical grinding and diamond anvil cell (DAC) devices are two common ways to investigate piezochromic materials. This review comprehensively summarizes the recent progress of piezochromic materials and their behaviours under hydrostatic pressure generated from DAC, in particular, different types of organic piezochromic materials. We describe their spectroscopic phenomena, discuss corresponding mechanisms, and intend to find the inherent clues hidden in the scattered literature.