You could achieve this using following code:
<div *ngIf="roleName === 'GC'">
You're a GC user...
</div>
<div *ngIf="roleName === 'GCDR'">
You're a GCDR user...
</div>
You could also achieve the same using ngSwitch directive:
<div [ngSwitch]="roleName">
<div *ngSwitchCase="'GC'">You're a GC user...</div>
<div *ngSwitchCase="'GCDR'">You're a GCDR user...</div>
<div *ngSwitchDefault>You're a unknown user ...</div>
</div>