The present communication deals with the hydrogen storage characteristics of C15 laves phase ZrMn_2–xNi_x system tailored within the x values of 1⋅25 to 1⋅50. Drastic variations in thermodynamics of the hydride phase is observed for any little changes of concentration x within this narrow range. The most promising room temperature hydrogen storage materials are found to be formed within the range of 1⋅35 to 1⋅45 where ~2⋅5 to 2⋅9 H/F.U. can be reversibly stored under the ideal operating conditions. The heat of the reaction is found to be ~17 kJ/mol, which means these are promising candidates for stationary and short range mobile applications. The phase structural features and the thermodynamic aspects of all the materials are discussed in detail.