An efficient di-tert-butyl peroxide (DTBP) promoted synthesis of oxindole has been developed. This methodology involves C(sp³)–H and C(sp²)–H bond activation under metal-free conditions. This synthetic approach towards oxindole synthesis avoids bases and hazardous iodine reagents unlike other methodologies developed so far. This metal- and base-free protocol is operationally simple and ecofriendly. It provides an expedient approach to access oxindoles in moderate to very good yields in DCE at 110 °C.