Incorporation of electron-deficient N-protonated 2,4,6-tri(4-pyridyl)-1,3,5-triazine (H3TPT) into electron-rich chlorocadmate leads to a novel organic-inorganic hybrid [H3TPT]2[Cd3Cl12] (1), which features as a trinuclear anionic cluster [Cd3Cl12]6- with one CdCl6 octahedron and two CdCl4 tetrahedra via edge-sharing mode and exhibits excellent photochromic performance with fast photoresponsive rate, obvious coloration contrast and high thermal stability.