Metal–organic frameworks (MOFs) as novel electrode materials have attracted intensive attention; however, low electronic conductivity hinders their practical application in lithium ion batteries (LIBs). This work reports the synthesis of conductive MOF/CNT composites with enhanced electrochemical reactivity. The growth mechanism of the pristine MOF and the correlations of two components are investigated from the viewpoint of crystal engineering. The time dependent morphology evolution experiment reveals that [Ni₃(HCOO)₆] undergoes an ‘aggregation-based nucleation-growth’ mechanism. As a result, [Ni₃(HCOO)₆]/CNT microsized ellipsoidal particles are controllably synthesized by tuning the reaction time and the reagent concentration, where CNTs penetrate the entire particles thoroughly. The obtained [Ni₃(HCOO)₆]/CNT composites exhibit significantly enhanced electrochemical activity in comparison with the as-synthesized pristine [Ni₃(HCOO)₆]. This is ascribed to the effective 3D conductive network constructed by CNTs. Our results provide an effective synthetic strategy to construct conductive MOF/CNT composites, which pave the way for developing other conductive MOFs for electrode materials.