One-dimensional (1D) S = 1/2 spin chains are a subject of long-standing interest, because conventional long-range ordering can be prevented and novel Luttinger-liquid phase may form due to strong quantum fluctuations. Recently, we first proposed the 4f compound, PrTiNbO6, as a perfect candidate for the 1D zigzag pseudospin-1/2 quantum antiferromagnetic chain. No magnetic transition was detected by heat capacity at least down to 0.1 K, suggesting the promising Luttinger spin-liquid ground state in PrTiNbO6. Direct probe of the ground state, spin dynamics, and excitations, as well as experimental determination of the crystal electric field parameters and the effective pseudospin-1/2 Hamiltonian, are now required to understand the interesting ground-state physics of the spin-chain compound, PrTiNbO6.