The coke plant/blast furnace will remain dominant for the production route from iron ores to crude steel.There exists a community of fate for the coke plant and the blast furnace as blast furnaces cannot be operated without coke for physical reasons. For cost optimization, it was and is important to minimize the coke rate in the blast furnace and to utilize the by-products of the blast furnace and of the coking plant. The paper discusses, for an interconnecting network of an integrated iron and steelworks, the potentials of the use of coke oven gas and blast furnace gas. The coke oven gas can be utilized for electric power and heat production, for conversion into hydrogen and methanol as well as reducing gas in the blast furnace or in a DRI plant. Blast furnace gas can be used conventionally for blast heating, coke plant underfiring and power production, or it can be recycled to the blast furnace in the nitrogen-free blast furnace process and in the plasma heated blast furnace process. A critical comprehensive assessment is also given for these potentials with respect to CO2 emissions.