Electroluminescent properties of polymer light-emitting diode (PLED)s fabricated from heterocyclic conjugated random copolymers, poly(PZV-ran-CZV), containing (N-2-ethylhexyl)-3,6-phenothiazinylene vinylene (PZV), (N-2-ethylhexyl)-3,6-carbazolylene vinylene (CZV) and phenylene vinylene (PV) unit as a light emitting layer were investigated. PLEDs made with corresponding alternating copolymers, poly(PZV-PV) and poly(CZV-PV), as a light emitting layer were also studied and exhibited EL maximum at 570 nm and 500 nm, respectively. Single-layered PLEDs made with poly(PZV-ran-CZV) copolymers, however, showed EL maxima shifted to longer wavelength. Double-layered PLED made with poly(PZV-ran-CZV) copolymer as a light emitting layer and Alq(3) as an electron transporting layer exhibited enhanced EL emission compared to that of single-layered PLED.