Recent studies have shown that thermal expansion of β-stabilized Ti alloys can be tailored along specific sample directions by controlling crystallographic texture and phase fractions. Early works demonstrated that these intriguing properties are due to the anisotropic thermal expansion of the orthorhombic αʺ martensite. However, the tailored expansion obtained via martensitic αʺ is limited by the thermal stability of martensite. Furthermore, αʺ is relatively soft and exhibits low Young’s modulus compared to widely used FeNi Invar alloys. Here, we demonstrate that orthorhombic αʺ_iso, the diffusion-based counterpart of martensitic αʺ, is equally, if not better, suited to regulate thermal expansion. Importantly, the temperature range in which tailored thermal expansion occurs is strongly broadened relative to the cold-worked martensitic alloy. In a first step, we clarify the formation path of nano-sized αʺ_iso during thermal cycling and resolve the crystallographic relationship with the parent phase. Next, we develop a novel strategy for creating multi-phase Ti alloys with zero thermal expansion and enhanced rigidity. By heating to between the start and finish temperatures for martensite reversion, the cold-rolled, martensitic microstructure of TiNb₂₂ transforms to austenite β, from which α′′_iso and ω phases precipitate during aging. The diffusional partitioning of Nb leads to the formation of β + α′′_iso + ω multi-phase microstructures. The crystal-level thermal expansion of α′′_iso is studied; macroscopic expansion behavior and Young’s modulus are correlated to the microstructural evolution during aging. Careful adjustment of the isothermal holding duration allows to engineer a microstructure that exhibits zero thermal expansion at an improved (i.e. increased) Young’s modulus. Such findings provide new routes for designing low/negative thermal expansion Ti-alloys with large operating temperature ranges and increased rigidity.