Summary: With the use of post-quantum or \((p, q)\)-calculus, in this paper we define a new class \(S^0_H(n, p, q,\alpha)\) of certain harmonic functions \(f\in S^0_H\) associated with a \((p, q)\)-Ruscheweyh operator \(\mathcal{R}^n_{p,q}\). For functions in this class, we obtain a necessary and sufficient convolution condition. A sufficient coefficient inequality is given for functions \(f\in S^0_H(n, p, q,\alpha)\). It is proved that this coefficient inequality is necessary for functions in its subclass \(\mathcal{T}S^0_H (n, p, q,\alpha)\). Certain properties such as convexity, compactness and results on bounds, extreme points are also derived for functions in the subclass \(\mathcal{T} SH(n, p, q,\alpha)\).