I used palladium catalyst in my reaction and afterwards ran TLC and I see a spot different from my starting materials. How do I conclude its the catalyst or my main product?
You could try running TLC with the Pd catalyst added as reference next to the reaction sample. As it contains a number of phenyl rings and transition metal, it probably will be clearly visible at the TLC plate - a nice, intense spot visible in UV. However, it might remain at the start position, but with this I am not sure.