We report here the structural, FTIR, optical and magnetic properties of Zn_1-xM_xO ceramics with M = Cu, Mn and (0.00 < x < 0.20)). For pure and doped samples, the wurtzite structure and compressive stress are confirmed. Further, a ductile nature is obtained for ZnO, but it is a brittle nature for the doped samples. As x increases to 0.20 for both dopants; the volume of the unit cell was decreased by Cu, but it was increased by Mn; the crystallite size was decreased, but it is higher for Mn than for Cu; the porosity, micro-strain, average grain size, and elastic modulus are increased, but they are higher for Cu than for Mn. While the Debye temperature θ_D is higher for Mn than for Cu and it is increased as x increases to 0.025 for both dopants, followed by a decrease up to x = 0.20. Interestingly, the energy gap (E_g) was gradually decreased by Cu as x increased to 0.20, whereas it was increased by Mn rather than Cu. Similar behaviors are obtained for the residual lattice constant ϵ_L and the density of charge carriers (N/m*). The loss factor (tan δ) is increased by Cu, whereas it is decreased by Mn. The optical conductivity (σ_opt) is decreased for both dopants, but the rate of decrease is higher for Cu than for Mn. In contrast, the electrical conductivity (σ_ele) was decreased by Cu, but it was increased by Mn. For Cu samples, a noticeable ferromagnetic behavior with evaluated magnetization parameters is clearly obtained. In contrast, the co-existence of weak ferromagnetic and strong super-paramagnetic behavior is obtained for Mn samples. These findings raise the question of the origin of RTFM and indicate that the addition of Cu to ZnO is promising for capacitors and spintronic devices. In contrast, Mn is convenient for devices such as optoelectronic, super-capacitors, magnetic imaging, and sensors, which strongly highlights the present investigation.