Observing GRB afterglows, SNe and their host galaxies with the 10.4 m Gran Telescopio Canarias (GTC)

We summarize the results of our programs started in 2009 with the 10.4 m Gran Telescopio Canarias (GTC) telescope. Since then its instruments have been subject of a continuous upgrade, making the GTC a competitive telescope for the GRB field. So far (Dec. 2012) the GTC have followed up 25 GRBs, measuring 10 redshifts, and discovering two SNe associated to GRBs. The new generation of instruments foreseen for the coming years will contribute substantially to enhance the knowledge of these puzzling explosions.