Concatenate two columns based on distinct values

1

C1–C2 --C3
A – 1 – RED
A – 2 – RED
B – 7 – RED

Concatenate C1 And C2 based on distinct value of C1

Out put i am trying to get to will show

A1
A2
B7

OR,

C1–C2
J–Smith
J–Alex
J–Smith

Desired output
J.Smith
J.Alex