Ni₄₃Mn₄₇Sn₁₁ and Ni₄₃Mn₄₇Sn₁₀.₅B₀.₅ polycrystalline alloys have been prepared by using arc-melting and characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), magnetization measurements and microhardness tests. Temperature dependent XRD measurements shows the evolution of monoclinic martensite phase (P12/m1) from the cubic austenite L2₁ (Fm-3m) phase. An enhancement (73 K) in the martensite transition temperature from 210 K for Ni₄₃Mn₄₇Sn₁₁ to 283 K for Ni₄₃Mn₄₇Sn₁₀.₅B₀.₅ was observed by DSC measurements, which is attributed to the increase in cell volume on the account of B doping. Microhardness measurements showed that the hardness reduces with B doping in Ni₄₃Mn₄₇Sn₁₁ alloy. The magnetic entropy change evaluated from the magnetization measurements was found to be 14 J/kg-K and 17 J/kg-K for Ni₄₃Mn₄₇Sn₁₁ and Ni₄₃Mn₄₇Sn₁₀.₅B₀.₅ alloys respectively. The effective magnetic refrigeration capacity at a maximum field of 5 T was found to be 94 J/kg for Ni₄₃Mn₄₇Sn₁₁ and 55 J/kg for Ni₄₃Mn₄₇Sn₁₀.₅B₀.₅, suggesting that these alloys have potential for magnetocaloric applications (magnetic refrigeration).