Concentration dependency of diffusivity in a multi-component diffusion system makes it complicated to predict the concentration profiles of diffusing species. This so called chemical diffusivity is expressed as a function of thermodynamic and kinetic data. DICTRA software can calculate the concentration profiles using appropriate mobility and thermodynamic data. It can also optimize the diffusivity data using experimental diffusivity data and store as mobility data which is a linear function of temperature. In this work, diffusion bonding of Ni using Cu interlayer is reported. The mobility parameters of Ni-Cu alloy binary systems were optimized using DICTRA/Thermocalc software from the available self, tracer and chemical diffusion coefficients. The optimized mobility parameters were used to simulate concentration profiles of Ni-Cu diffusion joint using DICTRA/Thermocalc software. The calculated and experimental concentration profiles agreed well at 1100°C. Agreement between the simulated and experimental profiles was less good at 1050°C due to the grain boundary contribution to the overall diffusion.