I wanted to stay at Emerald House, but honestly it seemed a little "away" from the main city walking areas. I ended up down there one afternoon and was kind of glad I didn't stay there. Wouldn't have been a big deal, just grab an Uber/Grab whatever, but... it seemed kind of on its own.
I ended up at the Holiday Inn Express (gasp!) but it was pretty central to a lot of things, easy to get to the metro, etc. (Holiday Inn Express Lisbon - Ave. Liberdade, an IHG Hotel, R. Alexandre Herculano 40, 1250-011 Lisboa, Portugal) real close to the Vintage.
If you're there a short while, look on a map drawing a line from the Maques de Pombal, walking down their big Champs-y main drag, explore down to the Praca do Comercio on the shore. Takes you by the Bairro Alto area, etc. Play tourist right and get on the cable car that takes you through most of the city, hop off for a bifana pork sandwich at Bourdain's joint, some pastais de nata, etc.
If you've got more time, Sintra castle-touring is a legit good stop. We also took an Uber to Cascais, that was really pleasant. Sort of a "Sarasota, FL meets Monaco" vibe.
Luminaries and the Pousada hotels (SLS hotels) seem optimal, Vintage not bad.