Nanosecond time-resolved emission measurements were performed on a home-built system using a continuous-wave 405 nm OBIS laser (Coherent) coupled to a pulse generator as the excitation source. A Cornerstone 130 monochromator (Oriel Instruments) was used when measuring the transient signals at 440 nm from 4CzBN. For transient measurements of upconverted light, a 300-390 nm band-pass filter was instead used after the sample to maximize the signal intensity. The signals were collected with a 9-stage PMT coupled to a Tektronix TDS 2022 oscilloscope. The optical response time of the PMT was set to be much shorter than the measured decay. All photophysical measurements were carried out in toluene using 2 mm quartz cuvettes. All samples were prepared in a nitrogen glovebox (Innovative Technologies) with <0.7 ppm oxygen levels and sealed with air-tight cap screws and parafilm. Temperature-dependent measurements were performed using a liquid nitrogen cryostat (Oxford Instruments) connected to a temperature controller.