Advanced materials with tunable thermal expansion properties have garnered significant attention due to their potential applications in thermomechanical sensing and resistance to thermal stress. Here, switchable colossal anisotropic thermal expansion (ATE) behaviors are realized in a Hofmann-type framework [Fe(bpy-NH2){Au(CN)2}2]·iPrOH (Fe·iPrOH, bpy-NH2 = [4,4′-Bipyridin]-3-amine) through a three-in-one strategy: vibrational mechanism, electronic mechanism and molecular motion. Spin crossover (SCO) centers coordinate with dicyanoaurate linkers to form flexible wine-rack frameworks, which exhibits structural deformations driven by host-guest interactions with iPrOH molecules. By means of vibrational mechanism, a scissor-like motion driven by the rotation of dicyanoaurate is observed within the rhombic grids, resulting in the emergence of colossal ATE in the high temperature region. When spin transition comes into play, electronic mechanism is predominant to form reverse ATE behavior, which is associated with host-guest cooperation involving significant molecular motion of iPrOH guest and adaptive deformation of host clathrate. A remarkably high negative thermal expansion coefficient up to −7.49×105 MK−1 accompanied with abrupt SCO behavior is observed. As a proof of concept, this study opens a novel perspective for designing dynamic crystal materials with tunable thermomechanical property by integrating various ATE-related elements into a unified platform.
