The photoluminescence (PL) from the I 1 centre is observed in p-, n-type as well as in compensated samples, using above band gap excitation. The PL from I 1 in the two polytypes 4H and 6H is very similar, the difference being the position of the main peak, in 4H 1.1521 eV and 1.1057 eV in 6H. We here suggest I-1 to be Mo related based on intentional doping, SIMS results and comparison with earlier reports of Mo in SiC using magnetic resonance techniques. From PL measurements, we analyze the electron structure of the defect, and suggest it be the neutral Mo (4d2) residing on a Si site, the luminescence coming from the transition between the 3A2 multiplet of the first excited electronic configuration and the ground state 3A2.