ngClass is not working in angular 4

ngClass directive generating the following error

ERROR Error: Uncaught (in promise): Error: Template parse errors:
Can't bind to 'ngClass' since it isn't a known property of 'li'.

code snippet.

 <li [ngClass]="{'active':true}"><a href="">Home</a></li>

NB: I already imported the common module

import {CommonModule} from "@angular/common"

Library version angular 4.0.1