Comapany without revenue can invest its funds to other companies

If company is NBFC registered with RBI then it can invest in the interest of the company. But if it is not, then it can invest for short term so that as and when business take off the funds can be made available to do business as per MOA . Of course it must take shareholder approval justifying the short term investment to earn some income by way of interest or appreciation etc

Holding investment company ,CIC ,NOHFC are some example