A thin-profile composite heat dissipating structure for a heat-generating electronic device includes a heat sink and a heat pipe, the heat sink includes a first housing, a first heat dissipation liquid, and a gas. The first housing is sealed to form a first cavity, the first heat dissipation liquid and the gas are received in the first cavity. The heat pipe is connected to the first housing and a wick structure to allow the return of the condensed heat dissipation liquid by capillary action is disposed elsewhere. An electronic device using the structure is also provided.