A police officer sent inappropriate messages to vulnerable women and visited a victim of domestic abuse late at night with a bottle of wine, a misconduct panel heard.
While working for Avon and Somerset Police, Jason Vernon also told one of the women, who he knew had mental health problems, that he "fancied" her.
The police misconduct panel found he was guilty of gross misconduct.
The force said Mr Vernon had resigned before he was sacked.
At a hearing on Friday, the Independent Office for Police Conduct (IOPC) said Mr Vernon had breached the "authority, respect and courtesy standards of professional behaviour".
A report by the IOPC found Mr Vernon had pursued an improper sexual, emotional and/or personal relationship by attending the home of a victim of domestic abuse with a bottle of wine and sending inappropriate emails to another woman.
It said he phoned one of the women offering to visit her between 22:30 and 23:00 the next day, saying that he "would help her find a job and a house" and that he would buy her the wine "just to be nice".
He then lied to a colleague, saying he was going to collect CCTV evidence so that he could visit the woman while on shift, arriving at her house with the wine at 22:35.
The report said Mr Vernon phoned and sent personal emails to another woman, despite having accessed information about her on the police log and being aware of her mental health problems.
The IOPC said he had "failed to act with proper self-control".
Operations manager Mel Evans added: "Police officers are expected to maintain the highest standards of professional behaviour and the misconduct hearing has determined, having considered the evidence, that the sanction of dismissal is the most appropriate outcome in this case."