a conversation is a talk between two people and a dialogue is talking to someone but they don't give a response they listen.

They're similar but I think dialogue is only between two persons. You can have a conversation with more than one person and it tends to be informal. Dialogue is rather formal.

Ther is a big difference. Dialogue is between two persons. Most part of the dialogue includes Questions and answers, requests and information. Dialogue is a conversational exchange between two people. Dialogue is for purpose. Conversation is talking between two or more persons. In talking you can say everything, even you can joke, you can tell a story, you can laugh. Conversation is informal interchange of thoughts, information, etc., by spoken words; oral communication between persons; talk; colloquy. Conversation is interactive, more-or-less spontaneous, communication between two or more conversants. Interactivity occurs because contributions to a conversation are response reactions to what has previously been said. Spontaneity occurs because a conversation must proceed, to some extent, and in some way, unpredictably.

Dialogue refers when exact two persons are speaking to each other (and so monologue when you talking to your self). In a conversation are more than two persons.