Thanks both for sharing your feedback. Apologies i forgot to mention, I want to fire a workflow associated with one list however getting it triggered through a smartform associated with another list as well. 

e.g. List 1 :  Submit button on new item smartform should trigger the workflow and same workflow should get triggered when I am firing a submit event of another list (which does not have its own workflow)

Hope i am able to make it more understandable now.

Dear ,

If u r using K2 studio , i do beleive u can do that , lets say ur workflow name is "Test"

go to ur First submit button , create a rule , when button is clicked , then add an action "Start Workflow" and choose ur "Test" workflow .

go to the Second submit button , create rule , when button is clicked , then add an action "Start Workflow" and choose ur "Test" workflow .

Hope it helps ,

best regards .