This work describes the important effects of microstructural features on crystalline structure, mechanical behavior and molten state response for poly (propylene-co-1-pentene-co-1-heptene) terpolymers. The study was carried out in a wide range of compositions, varying the 1-pentene/1-heptene ratio and the thermal history applied. Molecular features, as propylene sequences and compositional triads, allow predicting the material behavior. Moreover, rheological response has demonstrated the influence of molecular weight, comonomer content and short-chain branches on the properties. The flow activation energy can justify the importance of the material density over the whole spectrum of properties.