"In my project, the file size is exceeding 2KB"

The Raisonance free demo has a 4K limit, I think.

"I tried to split the program appropriately and created two hex files"

That can't work: that'll create two completely independent programs - each one will have its own reset vector, interrupt vectors, startup code, etc, etc

If you already have the full Linker, you might find that you can use the evaluation compiler to generate <2K individual objects and then use the full linker to link them into a >2K program?

Alternatively Browse or Search back through this forum, as a couple of free 'C' compilers have been discussed recently (SDCC is one of them)