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In this study, we explore the impact of donor strength on the photophysical properties of novel trifluoromethyl quinoxaline derivatives, which incorporate various electron-donating moieties exhibiting distinct conformational characteristics. The triplet harvesting mechanisms within these quinoxaline systems are facilitated through thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP), both of which can be modulated by subtle structural alterations in the donor unit. The derivatives demonstrate varying photophysical properties, including pure RTP activity, dual activity (exhibiting both TADF and RTP), and pure TADF, contingent upon the nature of the electron-donating moieties employed. Notably, the intersystem crossing (ISC) rates are significantly higher than the rates of radiative decay, leading to diminished fluorescence quantum yields (Φ DF) of the compounds in toluene solutions. However, embedding the TADF compounds within a rigid polystyrene (PS) matrix results in a remarkable enhancement of Φ DF due to significant reduction of nonradiative pathways related to intramolecular twisting. A considerable conformational disorder of the polymer doped films was observed resulting in non-exponential fluorescence decay and significant shifts of prompt and delayed fluorescence in time-resolved spectra. • Triplet harvesting in quinoxalines is controlled by structural changes. • Films with dibenzoazepine in PS show efficient PF and RTP without oxygen. • Phenothiazine gives mixed TADF/RTP, while acridine shows pure TADF. [ABSTRACT FROM AUTHOR]