High octane C7 hydrocarbons, particularly 2,2,3-trimethylbutane (“triptane”) and 2,2,3-trimethyl-but-1-ene (“triptene”) (collectively “triptyls”) are produced by homologation of a feed comprising dimethyl ether and/or methanol and optionally including one or more aliphatic hydrocarbons in the presence of certain acidic zeolite catalysts. The process can be carried out at temperatures lower than those previously used for conversion of dimethyl ether and/or methanol to higher alkanes, including C7 alkanes, and results in selective production of triptane and/or triptene with relatively little isomerization to or production of other C7 alkanes.