"I want to dynamically change the name in Data_1 every iteration using the loaded files. How can I do this."
Do NOT do this! Magically accessing/defining variable names is one way that beginners force themselves into writing slow, complex, buggy code. Read this to know why:
A much simpler and more efficient solution is to load the data into an output variable (which you should always be doing anyway, and then use struct2cell. Then your task is easy.
