Depends on what you mean by dual core.
The i3 is an ok 2 core CPU with hyperthreading allowing 4 threads.
The pentium series is a high performance 2 core cpu without multithreading: limiting it to 2 threads.
The celeron series is a low performance budget 2 core cpu, without multithreading. There is no reason to get it unless you want a low cost desktop build.
While the Pentium has much better single core (thus gaming) performance, a lack of hyperthreading means the 2 core limit breaks the CPU on some modern games designed to use 4 or more threads.