We investigate Caputo time–fractional quantum dynamics generated by a \(\mathcal{P}\mathcal{T}\) –symmetric complex periodic Schrödinger operator on the real line. The spatial part is a one-dimensional Schrödinger operator with an extended complex trigonometric potential that is L–periodic and \(\mathcal{P}\mathcal{T}\) –symmetric, and the time evolution is governed by a Caputo time–fractional Schrödinger equation of order \(0<\alpha \le 1\) with time-independent Hamiltonian H. Within a Bloch–Floquet framework we express the solution in terms of Mittag–Leffler functions of the Bloch band energies and obtain a band-resolved spectral expansion. For the finite-band Heun polynomial states of degree \(N=2\) we derive explicit evolution formulas and identify a finite-dimensional quasi-exactly solvable subspace. The analysis provides an analytic framework for Caputo time–fractional quantum dynamics in \(\mathcal{P}\mathcal{T}\) –symmetric complex periodic lattices.