In summary, a series of red-to-NIR donor-acceptor emitters were designed and synthesized, featuring relatively strong donor moieties (DMAC, PXZ and DPACz) paired with the PyBP acceptor unit. The structure-property relationships of these compounds were systematically investigated using computational simulations and photophysical measurements. We found that increasing donor strength leads to a significant red-shift in both absorption and emission spectra in solution and in doped films. Among the studied compounds, DMACPyBP, with the weakest donor, exhibits the highest ΦPL (62.3%) and the smallest ΔEST of 0.03 eV, with emission centered at 614 nm in 1 wt% doped CBP. Conversely, PXZPyBP, having the strongest donor, showed the most red-shifted emission at 638 nm (668 nm in 1 wt% PPT), but at the cost of a lower ΦPL (21.2%) and a relatively larger ΔEST (0.10 eV) in 1 wt% doped CBP. These findings compellingly illustrate that the proposed molecular design strategy is straightforward and has the potential to yield deep red TADF emitters for OLEDs.