Two-dimensional metal–organic frameworks (MOFs) have emerged as an attractive type of 2D materials, especially in surface-dependent reactions. And the colloidal stability of 2D MOF is crucial to its performance in surface-dependent application. This work provides a facile approach for directly fabricating 2D MOF with good colloidal stability by introducing monotopic ligand as modulator through coordination modulation. Modulator with methoxy group can effectively decrease the size of 2D MOF nanosheet and selectively modify MOF surface to improve its colloidal stability without changing its nanosheet morphology and porous crystal structure. The well-dispersed 2D MOFs provide more active specific surface area, which shows excellent catalytic performance in the synthesis of Schiff base. This method paves a new way to fabricate MOF-based materials with remarkable performances for surface-dependent application.