Solution-processed organic semiconductors are promising in joint-force with other semiconductors to push forward the printable optoelectronics field. Perovskite solar cell (PSC) is another promising new generation photovoltaic technologies, with the significant efficiency progress from 3.8% in 2009 to today’s 28% PSC. The stability is the biggest challenge in PSC and organic semiconductor could provide valuable assistance. I will report efforts in Hong Kong adopting organics semiconductor concepts to improve the PSC efficiency, stability, and in particular removing the reverse-bias resilience challenge in perovskite solar cell via tandem solar cell structure with OSC. Recent research results on stretchable organic solar cell, organic light emitting devices (OLEDs), and practice in stable perovskite LEDs will also be presented.